So I watched the Labyrinth a few nights ago. Again . And got an idea for a campaign setting. An island, somewhere, that is an insane everchanging labyrinth in its entirety. Once you get in, it is a next to impossible to get out again. The whole setting would be built of huge amounts of small detailed areas, which interconnect randomly. So when the players go from one area to the next, the GM just rolls to see where they end up. You could be in an actual walled maze area one moment and walk through a door and you're suddenly standing next to a waterfall in a thich forest. The door slams shut behind you, and as you open it again, it opens to a little idyllic village...

I was also thinking that the island could be divided to a dozen or so thematic districts so that it wouldn't be completely random where you end up. You could for example end up only in areas that are on the district you're in, or to one adjacent.

As a starting point I made a topographic map for the Island.

And a few small encounter areas, courtesy of hafrogman (have to think what to do with these but they do sound interesting):
Bay of Frogs (I guess there might be some Kua-Toa)
Feast of Galeros (Either a skill challenge where PC's must eat, eat, eat, or some form of Hero's Feast)
Cult of the Hive (Well there must be somekind of insectoid queen here. Or Borg )

Blackrat