In my efforts to collect the links below, I've also come up with a couple recommendations about writing play reports.
First, it really helps if you tag/label your posts.
Ideally, tag your posts both with whichever "actual play" synonym you're using, as well as a second tag with the name of the campaign. Sometimes it's nice to see all of someone's play reports together, and sometimes it's nice to see the play reports for one campaign interwoven with posts laying out setting materials for it. Without tagging, it's very difficult for anyone to find your old reports. At best, they can try to expand all the month and year folders in your archive, and look for post titles that sound like they might be actual play. The gold standard, if you feel up to it, seems to be to create a static page of links to all the reports in a single campaign, so that people can easily read them in order.
On my own blog, the games where I'm the referee are tagged as session reports, and the games I play in are tagged as play reports.
Second, narratives are easier to read than transcripts. If you want to quote yourself or your players directly, be warned that a little goes a long way, and a lot is probably too much.
Third, practice every good writing skill you know. Some of these reports I like much more than others. Another time I might try to understand what separates my favorites from the ones I like least. For now, let's say that it's probably best to go with a conversational style. Some people can write within-fiction accounts well, either fictional news report from within the campaign world or fictional first-person narratives allegedly written by player characters - but it's my impression that those are more difficult to do well than talking through it in plain language. Frequent paragraph breaks are your friend; a wall of text is not. The right amount of detail is a balancing act, but it's probably better to highlight a few amusing anecdotes and summarize things that happened in a straightforward fashion. Personally, I also enjoy hearing from other referees how they made certain decisions and rulings as a kind of post-mortem, but the absence of that analysis also won't doom you.
Probably the first "actual play" reports I ever read were written by Jeff Reints. As far as I know, the first campaign he blogged about was his Cinder campaign. A few years ago, he probably would have been most famous for his Wessex campaign, also known as "The Caves of Myrrdin". More recently, you might have heard of his Vaults of Vyzor campaign. I really love the fake old first-person dungeon crawler CRPG graphics he put together for his Vyzor posts. You can see an example below. (Jeff's players also create a lot of maps and art, and he posts a lot of it in the session reports. It livens them up even more.) Jeff doesn't tag his play reports separately, but he does tag them with the names of his campaigns, so you'll see the reports alongside all the things he creates for them. It was much shorter lived, but he also ran a few sessions of Doom of the Jaredites, a hexcrawl based on the Mormon myths about the lost tribes of Israel settling in the American southwest.
Roles, Rules, & Rolls
Roger ran at least two campaigns that I'm aware of. One was to send players into the Castle of the Mad Archmage megadungeon. The other was his Trossley campaign. Roger tags the campaigns, but not the play reports. Over the course of those two campaigns, he wrote his own Cellar of the Castle Ruins dungeon level, that I believe fits directly above the CotMA. Frankly, it's worth checking out everything in his "Rules and Tools" sidebar. You can see a map of the Cellar below.
Telecanter's Receding Rules
Telecanter didn't start out tagging any of his posts. If you browse his archive, you can find a number of early play reports by looking for entries that have the same name, followed by a Roman numeral, for example in September 2009, he has a series of posts about a game he called Epithalamium. Later, he started tagging his play reports as either post-session narratives or post-mortems. These overlap a lot, and most reports are tagged with both, but there are a few you'll only see by looking at one or the other. Like Roger, a lot of Telecanter's games featured a dungeon of his own making, the Coastal Caves, which is in the one-page dungeon format. You can see an image of the map below. Telecanter wrote a lot of really interesting free content, and I highly recommend checking out the links along the top of his blog, all of the really, but perhaps especially the DM Aids.
Dreams in the Lich House
John's blog is pretty much just setting creation and play reports, and the settings he creates for his campaigns are all pretty memorable and interesting. He doesn't tag play reports separately, so you'll find them interspersed among his campaign materials. His Gothic Greyhawk campaign is the oldest one I'm aware of him writing about. I started reading his blog while that one was coming to a close and his next campaign was getting started. It's one I've written about before, the famous Black City campaign, set in an alien city on a frozen island in a north sea, explored by pirates and vikings. Next he spent a fair bit of time building a Harrow House campaign, but I don't think there are actually any play reports in there. Instead I think he ran an ancient Greek themed version of the same idea, which became his Taenarum campaign. He ran one of the only Dwimmermont campaigns I've seen. More recently he started a 5e Illyria campaign, although it didn't last long. If you were going to check out additional materials on John's blog, I'd definitely recommend looking at the collected links for the Black City project.
Chris writes about his game sessions using a fictional news gazetteer. Usually he ledes with rumors and information to set up the next session, but usually follows up with information about what happened at his table recently. He also ran a Traveller campaign that he wrote about too. I've praised Chris' writing about undercity pointcrawls before. Another very cool idea of his is the Chaos Index, which allows player hijinks to cause escalating metaphysical disruptions to the campaign setting.
Tales from the Sorcerer's Skull
Most of Trey's recent play reports take place in his own wonderfully Oz-ian Land of Azurth setting. (It reminds me a lot of Wampus Country, as well.) Trey seems to frequently use well-known adventures, but re-skin them. Most recently his players visited a Yellow-Submarine-themed Misty Isle of the Eld, and before that they went to Castle Amber. Trey has a couple of books that collect his Weird Adventures and Strange Stars settings. He's currently working on something with Silver-Age-style supervillains, and (much beloved by me) his slowly accumulating science fantasy setting. The map below comes from his unnamed science fantasy world.
Tales of the Grotesque & Dungeonesque
Jack meets my gold standard for play report tagging. All his play reports share a common tag. Each play report is also tagged with the campaign it took place in. And then his two longest-running campaigns - Krevborna and Umberwell - both have static pages so you can find all the reports in chronological order. I've actually played in Jack's Umberwell campaign.
For any of these play reports, good writing helps, but it's probably also important that your session was lively and your players enjoyed the experience. I don't think there's any writing style in the world that could make it enjoyable to read about the kinds of online games where you explore two rooms, spending half the session trying to solve a puzzle with no clues, and the other half in excruciating slow combat. Jack's sessions (that I've played in at least) typically involve a fair bit of exploration and investigation to gather clues, with a climactic battle at the end once you understand enough to confront and fight the source of the mystery.
Dungeon of Signs
Gus labels both his actual play reports and tags the individual campaigns they belong to. His play reports are mostly divided between four different campaigns. The first campaign Gus ran was based on the Anomalous Subsurface Environment, although it mostly took place in the campaign world outside the famous megadungeon, rather than inside it. His second campaign (or family of campaigns) is based inside his own HMS Apollyon setting. Gus also played in a Wampus country campaign (hosted, unsurprisingly, by Erik from the Wampus Country blog) and a Pavelhorn campaign (hosted by Brendan from Necropraxis). Gus wrote quite a few dungeons and adventures, and you can find them on his PDFs to Download page.
Monsters & Manuals
Nomisms writes lots and lots of setting material, including his well-known Yoon-Suin setting, but he has relatively few actual play reports. (He may have slightly more than I realize, because he tags his campaigns, but not his play reports, the two I found here are campaigns that only exist as actual play.) His Cruth Lowland campaign is, I think, set in a kind of Dark Ages northern Britain. Three Mysterious Weirdos takes place in a fantasy Edo Japan, much like his Valleys of the Winter People setting materials. Some other fun settings he's developed over time on the blog are Behind Gently Smiling Jaws, an Inception-style campaign that takes place in the mind of a dreaming immortal crocodile; New Troy and There Is Therefore A Strange Land, both of which are high-fantasy with fairy knights and interdimensional travel; and two I'm especially fond of - a planetcrawl through fantasy moons of Jupiter, and The Fixed World, where different parts of the world are always the same time of day and the same season, so Always-Winter-Always-Morning is near Spring-Morning and Winter-Noon, etc. You can see his map of it below.
In Places Deep
Almost all of Evan's play reports are from his long-running Nightwick Abbey campaign. If you've heard of Evan before, it's probably because of Nightwick, which you can see a partial map of below. I briefly played in one of Evan's online games, maybe a session or two, in his ancient Mesopotamia inspired Uz setting. More recently, Evan's written a couple of good retrospectives about what it takes to run a megadungeon campaign for as long as he has. Like Hill Cantons, most of the play reports here take the form of within-campaign fictional news reports. (I don't know the best way to assemble players for an open-table online campaign, but putting out a call for players on his blog seemed to work for Evan the time that I played.)
Hack & Slash
Courtney's session reports are mostly from awhile ago, and most of them are transcripts rather than summaries. Unfortunately, we don't get to see any of the actual play that goes into his Numenhalla megadungeon, pictured below. Courtney's blog shares a lot of his thoughts on player agency, and his great love for dungeon tricks and traps. Recently he's been publishing Numenhalla in segments, alongside advice for running a resource-management heavy megadungeon campaign using 5e.
Zzarchov's recent play reports are from his Xanthandu campaign, seen below, which I believe is set in a kind of fantasy Polynesia, or at least some sort of fantasy tropical island with a French colonial governor. A few are Neoclassical Geek Revival games (for which he also has example-of-play transcripts, which I am given to understand are lightly fictionalized versions of real events, emphasizing the use of his houserule mechanics). Zzarchov also played in Evan's Nightwick Abbey game, so some reports on that appear as well. If you recognize Zzarchov's name, it might be because he has written quite a few adventures, including Scenic Dunnsmouth, which uses dice-drops and playing cards to procedurally generate a Lovecraftian village, and Price of Evil, which uses similar techniques to generate random Gothic haunted houses. I'm also quite fond of his "seed tables" for generating random wilderness hex contents. These are each three related 1d8, 1d6, and 1d4 tables, where rolling triples 1-4 or doubles 5-6 gives additional results, which I think is a smart use of the dice.
Patrick's earliest actual play posts are all his adventures in other people's campaigns. He mostly wrote these as first-person within-fiction narratives. More recently, his posts are about games he's running. First in his Islands of the Imprisoned Moon campaign, which I think takes place in a fantasy Polynesia, and second in his Syr Darya campaign set in Nomisms from Monsters & Manuals' Yoon Suin. His most recent post covers something like 11 sessions in one long go. I've mentioned Patrick's Deep Carbon Observatory on here before, and he also wrote Veins of the Earth (among others).
Blog of Holding
Paul has only a couple groups of play reports. He has one series of actual play in a setting based on the fictional game Mazes & Monsters. He has another series of play reports from a game he played with D&D designer Mike Monard. Paul doesn't really tag any of his posts. Those two series are unusual because they are tagged - but my favorite group of his play reports aren't. My favorite is Paul's "Downton & Dragons" campaign which combined D&D with Downton Abbey, and took place in four parts. You might have heard of Paul from his project to turn D&D's "random dungeon generator" into a dungeon map.
Justin's play reports all take place in his Ptolus campaign. After each play report, he also posts a post-mortem talking about some gamemastery decision he made for the session. Justin's blog also meets my gold standard (and may actually represent the high-water mark for organization) since he not only tags his play reports, and his post-mortems, and the campaign itself (so that you can view both together), he also has an index page linking to each entry. Justin's blog is also a treasure trove of good advice and interesting ideas, and he wrote the "Halls of the Mad Mage" dungeon that I've used on a couple occasions.
Probably the best way to read Planet Algol's play reports is to go over to the sidebar of his blog, scroll down past the images, and start at the beginning of his "Algol Adventures" links. However, he has more play reports than show up in the sidebar, and there is a tag you can use to find them. While you're there, it's probably worth checking out his page of links to many of his campaign setting materials.
Anomalous Subsurface Environment was one of the first OSR megadungeons, and I remember seeing someone point out that the guy who wrote it also had a hilarious blog where he wrote about his players exploring the place. It's really good. Pat does tag his play reports, but honestly, most of his posts are play reports, and the relatively few that aren't are all about him designing rooms and traps and monsters.
People Them with Monsters
Jeremy didn't write a lot of session reports, but they were mostly related to his evocative Outland campaign setting. Outland really captured my imagination, especially with the cool house rules document and cool character sheet. You can see a map of the setting below. Outland was similar to one being outlined by another blogger on the now-deleted blog called "A DM's Tale" (or something pretty similar). Both settings were human-focused, but had things like morlocks and demons rather than elves and goblins. It helps that Outland has a good name, for sure, but I liked the variety of weirdness he was creating (and I appreciated his willingness to admit in his reports when things didn't go the way he'd hoped). Today you might know Jeremy from his very helpful DCC reference document.
In their own ways, I think Planet Algol, ASE, and Outland are all inspired by or were responses to Geoffrey McKinney's Carcosa setting. Carcosa came out a little before my time. By the time I started reading gaming blogs, Geoffrey had already deleted his and gone into semi-retirement. I wasn't there to see how people first reacted to his setting. I think I first read about it in some RPG trivia post that listed it alongside FATAL and The World of Synnibarr. But for people who were around at the time, it seems like the combination of sci-fi, fantasy, and weird horror tapped some deep vein of interest and inspiration. Which is probably why Carcosa is still interesting and still popular today. It's also why I still find Planet Algol, Henchman Abuse, and People Them With Monsters worthy of revisiting.
Paul's play reports are divided between two main campaigns. His more recent one is his Rifts misadventures campaign. Before that, he had a Demon Verge campaign, which was based on an idea Jeremy from People Them With Monsters also had - to use Dwarfstar games' Demonlord boardgame map as a wilderness hexmap. This is an idea I love, and so I really enjoyed reading Paul's reports on his campaign there.
Redbox Vancouver & Redbox Niagra
These aren't individuals' blogs, they're blogs maintained by D&D clubs. They're connected to, or share members with (I think?) Planet Algol, The Mule Abides, and the whole Dungeon World scene.
I first learned about them because RBV played some sessions in the Anomalous Subsurface Environment as part of their White Sandbox campaign (check session 40 to see what I mean). Poking around, I discovered that their Black Peaks campaign included adventures in Stonehell, and that they had a brief Planet Algol campaign as well.
Separately, reading about Barrowmaze on Discourse & Dragons led me to RBN and their ongoing campaign through Greg's dungeons, including now Forbidden Caverns of Archaia (Which is great, because Greg doesn't tag his play reports - there are plenty of entertaining adventures, but you really have to scour his archive to find them.)
It's really fascinating to read these guy's play reports, because they're clearly interested in old-school gaming, and obviously getting together frequently to play old-school D&D, and yet they're socially almost entirely disconnected from the corner of the OSR scene that I'm most familiar with. Reading their reports is like looking into some parallel world.
Savage Swords of Athanor
Doug's is the last of the old blogs in the "so old they're now defunct" section of my list. I think all of his play reports take place in his pseudo-Roman setting of Estarion. Like Jeremy from People Them With Monsters, he also has a cool house-rules document. In the sidebar to his blog, Doug also has a series of setting documents you can download. They're less like zines and more like a broadsheet or gazetteer, but still kind of cool and worth checking out, especially if ancient Rome is your thing.
Papers & Pencils
As I mentioned up at the beginning of this post, Nick is the one who inspired me to kick this whole list off. He doesn't actually tag his play reports, but he does maintain an index for each campaign, linking to each session in order. His first campaign was Dungeon Moon, which was huge and probably over-ambitious, and I like that he talks with humility about what he wanted to do and what went wrong. While it was too hard to run as a judge, if Gus from Dungeon of Signs is any indication, the players all enjoyed the depth and scale of the place. Nick's second campaign was On a Red World Alone, which was set on Mars, the eponymous red world. His most recent campaign, and the one whose index he just published recently is Fuck the King of Space, where the goal and attitude are pretty much exactly what you'd expect from the name. I like science fantasy and even just regular fantasy set in space, so I'm particularly fond of that aspect of Nick's GMing. In terms of referee advice, Nick's also written a list of post-game questions for the ref to ask themselves to help guide preparations for the next session. Several new bloggers a little further down my list have adopted these and started adding them to the end of their own session reports.
Bernie the Flumph
Josh's play reports tend to alternate between a campaign set in Sine Nomine's Silent Legions, and various DCC adventures. I've played online in a game Josh was running once, set in his own Sanctum of the Snail adventure. I enjoy Josh's love for mollusks, and his personal quest to stat up the Flumph in every ruleset he can.
Against the Wicked City
Except for one early post about playing D&D with his toddler son, all of Joseph's play reports are about a group of players collectively known as Team Tsathoggua, who've been adventuring in a fantasy Southeast Asia that includes the Island of Purple-Haunted Putrescence and Qelong. Joseph's players are full of schemes, and seem to be constantly trying to set themselves up as local rulers. Joseph's campaign materials outside this game mostly focus on his linked Wicked City and Great Road settings, which are part of a fantasy Central Asia. He also writes reviews, mostly of horror-themed adventures and rulesets, most recently a series of posts about the newest version of Warhammer Fantasy Roleplay. You might also know his essay on the aesthetics of ruin, or his collection of weird character classes that's available to download from his sidebar.
Coins & Scrolls
Skerples has an ongoing campaign with a fairly stable group of players. Over time, his play reports have transitioned from being set in his own Tomb of the Serpent Kings and Steam Hill dungeons to taking place in his version of The Veins of the Earth. Skerples is notable for being very into accurate medieval and feudal history, while running a game where most of his players are insect people. (Technically his list of player races includes many non-insect options, but in practice, his games end up feeling more weird than if his players mostly played as hedgehogs and mice.) Skerples is also and enthusiastic adopter of the Goblin Laws of Gaming, making him one of the founding members of what I would consider to be the slightly separate GLOGosphere of OSR bloggers. (You can see all of Goblin Punch's GLOG posts here, and find all the pdfs of his rules here.) You may also recall that once when I was reviewing Skerples' vignettes of fantasy epochs, I said something like "Skerples should collect these into a book and offer it for sale." Well, Skerples did in fact collect them into a book and offered it for sale. My influence on the project is parodically denounced in the acknowledgments.
Throne of Salt
Dan is also part of the new crowd of GLOGosphere bloggers. His recent play reports all take place in his own planes-hopping Danscape setting. His games sound fun, and they remind me of that fact that virtually anyone who runs an online game with an open table that they announce on G+ is going to end up with a veritable "who's who?" of celebrity players. (Well, as "celebrity" as it gets among the OSR blogosphere anyway. But Dan's games end up being just as much celebrity games as Jeff of Jeff's Gamesblog's do.)
Tamas has apparently been around for a few years, but I only just found his blog. He doesn't have many play reports, but there's quite a bit of variety, ranging from a Conan-style raid on a wizard's tower, to Cavegirl's Game Stuff's Gardens of Ynn, to his own adventure inside a giant fish.
The Scones Alone
Brian's blog is pretty new, so he only has a handful of play reports, all set in the same campaign, exploring A Red and Pleasant Land using Into the the Odd rules. Still, his reports are interesting, I appreciate his self-reflection, and there's a soft place in my heart for anyone who attempts to bring in NES games like Dragon Warrior and the original Castlevania as inspiration for their games.
Most of Jonathan's recent blog posts are actual play reports. I heard about Bearded Devil from seeing someone praising his hand-drawn city maps. They are gorgeous. He also draws headshots of all his player characters and NPCs. So I came for the art, but the play reports themselves are lively and interesting. One recent game took place in a city built inside the stomach of a flying psychic whale. Another involved an evil alchemist who was synthesizing fake royal jelly to usurp the throne become the false queen of the wasp-women.
People who run games seem to be much more likely to write play reports than players are. (And the players who write play reports seem to be players who are themselves also judges and referees.) I take notes almost every time I play or run a game, but I admit, I'm not always fast to write them up properly. Probably there are other people in a similar situation.
Despite this, I do think there's a real value in people sharing their gaming experiences. Seeing how other people run their games can give you ideas for things you want to do (or things you desperately want to avoid doing!) and it gives you a sense of what the community is like, what other players and other judges are doing at their tables. If you want to know what works well, what's hard to pull off, what people usually pay attention to, and what they ignore, there's no better way to find out than by reading play reports, especially if they come with some sort of post-mortem talking about how the referee prepped, how they made key decisions, or anything else important that came up during play.
I really like learning what's unique about people's home campaigns, but I think it's also quite valuable to see what happens when two different judges or two different groups play through common dungeons, or use two versions of the same campaign setting. First because it's important for a community to have a shared repertoire and language, a shared collective memory of key or formative events, and secondly because it's by seeing how different people interpret the same game text that you really learn how the game is played, you really see what's possible within the structures the game establishes.
In addition to post-mortems, I also really like to see lists of the player characters and retainers, lists of encounters/combats, lists of treasures found, and lists of XP awarded. Papers & Pencils' list of post-session questions might also be catching on. I find that these kinds of summaries are a good GM-aide (I often don't know how much experience to award until after I've gone through the list of everything the players did while writing up the report), and I enjoy them as a reader as well. Not only do they help me keep track of all the moving parts of the session report, they again show me how different judges adjudicate similar situations.