Check out the movie The Craft, or the movie The Gate. In both films they try to levitate someone in this manner. When we use to try it as kids, we would have someone lay on the floor and close his/her eyes. Then you would get at least three people around that person and stick your pointer and middle finger under them. Then chant "Lite as a feather, Stiff as a board." It may freak some people out, but if that fails, a Ouija board always seems to be a hit.