A small steel ball and tube are passed out to the audience for examination. The ball clearly rests on the top of the tube, being too large to pass into the tube. The magician, without touching the ball, and holding the tube only, commands the ball to slowly sink into the tube and slowly rise again: a demonstration of mind over matter you say. Everything is then passed out for inspection.
This stunning bit of close up is extremely easy to do, requiring little practice.