Traps that squash people, traps that move (not too quickly because sometimes it's actually REALLY difficult to get across) and those traps that disappear and re-appear every now and then (if you do this, make sure it's not a long stretch of just this trap, make this part short-ish)
You could also do a trap where the floor disappears and moving platforms appear (although, I find this annoying because it takes more time to complete the actual map :P)
Kienio got a reaction from Rewbin in Traaps