Amazingly make a clip link onto a rubber band. You hand to the spectator all of the objects: one rubber band and two clips, each of them with a different colour. They examine it all, and after that, you put one of the clips clearly onto the rubber band. You do the same with the other one, but with a very visual effect. So, the clips are now linked onto the rubber band. Then, while you perform the unlink in a joking manner, you ask for the spectator to put his hand under the rubber band. Finally, you unlink the clip in a very magical way.
IMPOSSIBLE AND VERY VISUAL EFFECT
Part 1 Part 2