Traps and Puzzles for an Ancient Elven Ruin

[Clicky]

My party has just entered its first mega dungeon of the campaign. My co DM and I have several levels planned out already, but we need to fill them with clever puzzles and traps before next session. We really don't want the "find/disarm or take damage" type traps common in most dungeons. So almost everything SRD or Grimtooth is out. They need to be clear tests of wit that our party can talk through and figure out to pass through. The elves who built the place were basically trying to make sure that nobody dumb could get in. Any suggestions?

[VoxRationis]

Some sort of enchantment that makes them always loop back to the entrance unless they fulfill certain requirements, which may be puzzled out through correct interpretation of a riddle. Very elven in character, that one.

[Gildedragon]

Things that require Kn Checks
Like a room where the door is hidden in a pillar, requiring a Kn Arch to realize that the pillar is not load bearing, or that the rooms are too small to account for the size of the temple.

a kn religion to know what item is the odd one out in an iconographic wall, or which religious implement is fake, or that certain undead creature is of no risk and can in fact answer questions

a kn nature to identify certain plants need running water, and thus there is a river/passageway beneath the floor

a kn dungeoneering to be prepared against certain ooze/aberration encounters

[Jeff the Green]

Something involving archery, possibly like Odysseus's proof that he was actually the king of Ithaca (string his extremely stiff bow and fire an arrow through the holes in a bunch of axes lined up).