A REALLY GOOD PRANK TO PULL(NOT HARMFUL)

It can be on any day....but a warm/hot one would probly be best. Take a cup full of water (make sure the cup is glass, plastic,...ect. Just not paper. ) and a tack....this is all you will need. Gather a few people around and tell them that you can tack the cup full of water to the wall. Hold the cup up to the wall and on purpose drop the tack (dont tell the people this) but ask somebody to get it for you because you are holding the cup to the wall and you dont want it to break. The person who bends down to get it for you, pour the cup of water on them!!!!!