I remember one of those candid camera shows, where they would find tourist couples taking pictures of each other at a castle or something... the prankster would offer to take a picture of the couple for them, and slowly back up to frame the picture till he fell backwards over the low wall at the edge of the cliff... and the hidden camera would catch the terrified tourists running over to see the guy laughing on a mattress on a ledge about 3 feet below the edge. It was HYSTERICAL.