[TealJade]

I think they should do a scavenger hunt. Start some where like your home page or profile with a clue, can't see the other next clues until you have figured out the first one and so on.
There could be small prizes along the way and a large prize for who solves the clues in the best time. Different people's clues are in different orders so people couldn't cheat and tell others who logged in later.