I have a fondness for Sample Dungeons. Not just the Zenopus dungeon - all of them from various TSR products. So I enjoyed reading Timrod's new series at Unfrozen Caveman Dice-Chucker delving into the 1E AD&D DMG Sample Dungeon (by Gary Gygax). There are two entries so far:
As an aside, a redrawn version of the map for this dungeon appeared again as a sample dungeon in the 3.0E DMG, and then a finished 3.0E version of this dungeon by Jonathan Tweet appeared in Dungeon #84 (2001) under the title Dungeon of the Fire Opal (still available from Paizo as a pdf).
Edit: Here's the Dragonsfoot version of the DMG Sample Dungeon. It's called The Monastery of the Order of the Crimson Monks, and is for levels 5-9: