Seven tricks you can do with empty rolls of toilet paper, written by the late Martin Gardner.
5. A Mysterious Force: Two tubes are alongside each other on a table. Rub your hands vigorously together to generate a psychic force. Place your hands palms down fingers pointing toward the tubes. Lower your head slightly. Move your hands slowly away from the tubes, and at the same time secretly blow on them. They will roll toward your hands as if drawn by a mysterious attractive force. You'll be suprised at how many people will be totally mystified by this simple trick.