Like Bilbo, I also enjoy maps, particularly dungeon maps; and especially ones that have some kind of trick to them. Today, I happened upon what may be the tricksiest dungeon map of them all:
Just look at all those discs ready to spin around and completely befuddle any adventurers wandering through. This beauty is the brainchild of James Eck, who's also written up a short module utilizing the design. Stats, when necessary, are given for both D&D 3.5 and the author's own Mind Weave system, but honestly there are so few numbers involved it would be a cinch to use with any system you care to name. Plus there's a few other interesting tidbits, like the single-use keys that respawn in portable - but heavy - chests. Very Zelda-esque.
But that's just a bonus - the map could easily be re-stocked for better integration into a campaign, or you could use some random tables to just let the madness build. You might even transplant it to another genre entirely - I'm thinking Indiana Jones would have a field day with the place.