Probably not what was expected, but there were some neat traps in LittleBigPlanet. Yes lots of them were simply timed events, and if you watched, they would cycle, being harmless. But if you were trying to do a speed run through a level, jumping at something to have it vanish or become deadly was always hilarious.
My very favourite is the last level, its not even noticable unless you're playing on co-op. As you reach the final boss part, to prevent you from backtracking at this point, the passageway behind you slams down when you reach a proximity trigger, which is well clear of the passage itself....But....lets just say the slacker co-op player was trailing behind being silly, and that roof slamming down on them instantly, left me in stitches.