|The map of The Tomb of Ra-Hotep. Source: Paul's Gameblog|
Delta has a report on running the Tomb of Ra-Hotep, the OD&D dungeon by Alan Lucien that inspired Gygax's Tomb of Horrors (and Necropolis, it seems). It was included as an extra in the reprint of the original tournament version of Tomb of Horrors, which was itself an extra with the Special Edition of last year's Art & Arcana.
Mystical Trash Heap: Art & Arcana First Impressions
Paul's Gameblog: Credit Where Credit's Due
Locations for the Tomb of Horrors on the Great Kingdom Map