I've been running The Abduction of Good King Despot, published in 1988 as part of New Infinities Productions, Inc.'s generic "Gary Gygax Presents Fantasy Master" line, adapted from a 1E AD&D (OD&D?) tournament module from the 70s. It was one of the first modules to be published in a consciously "retro" style (anticipating Hackmaster, DCC, etc.) and "feels" much more 1978 than 1988 -- heavy emphasis on puzzle-solving and challenging the players' intellect as much or more than the characters' abilities, no attempts at "ecologizing" (except for a couple things that play more as jokes than serious explanations), and lots of humor -- to the point that the module veers close without quite dropping over the ledge into "joke module" territory. I've had this module since its release, it's always been one of my favorites, and I ran part of it (never finished) for a different group of players (guys from the local game club) c. 1989-90.
I'm running the module using 1E AD&D rules (simplified in an OD&D-ish direction) and using the module pretty much as-written (with allowance for the fact that as published it has generic stats so I had to fill in specific AD&D monster stats, spells, magic items, etc.) -- but the "plot" and the encounters are all straight per the module. It was originally written assuming 8 players and I've got 4-5, so I've toned a few combat-oriented encounters down a bit (8-headed hydra becomes 6-headed, 4 griffins become 3, etc.). After 2 sessions the party has made it through about 1/3 of the "plot" and about 40% of the page-count of the module. They haven't yet figured out any of the patterns which would help them to make sense of the place (and, presumably, make more efficient progress). Alas, in the second session because they got stymied by an obstacle they went backwards and visited all the red-herring rooms they'd skipped over in the first session, which was fun for them (they got to kill some more things and take some more stuff) but a trifle annoying to me for two reasons: 1) I wanted them to keep making forward progress (because I generally like the second half of the module better than the first half -- the puzzles are harder and IMO more interesting), and 2) I was hoping to perhaps recycle some of the unused encounters/traps/puzzles into my own dungeons.
The players are all familiar with 1E AD&D (it's the only thing we've been playing for the last 2.5 years) so there's nothing new there, but the other DMs (I was just sitting in while our regular DM was out sick) have tended to run more serious/logical/story-based games so the "funhouse" style of this dungeon (where you can have, say, a lady with a pair of pet bulls in one room, a pair of frost giants down the hall, and then a giant crab in the next room) has been a change, but they've been rolling with it (maybe too well -- I think they've accepted the funhouse atmosphere so unquestioningly that they're not even looking for the actual logical patterns that are there) and even those players who prefer more story and NPC interaction and are probably glad that all our games aren't like this have been enjoying themselves, so I consider it a success.
We're currently on hiatus for XMas, and presumably our regular DM will want to resume the chair now that he's finally recovered from illness, but I'm keeping this on the back burner and hoping that sooner or later we can schedule another 2-3 sessions to finish this module (especially because, as I alluded to above, I think the best parts of the module are still to come).