An excellent and entertaining effect using two cylinders, two bottles and a lot of audience participation.  A bottle & a tube are each chosen by a spectator and the magician.  The idea is that the spectator is to copy the magician in everything - Here's where the fun starts, the bottles go into the tubes, the tubes turned over and back, no matter how closely the spectator follows the magician's movements, the outcome is never the same.  The bottles are exchanged, but the spectator is still unable to copy the magician.  To finish, the magician magically makes the bottle turn over in the tube to match that of the spectator's.

Superb entertainment for both children or adults, the trick they'll remember as a major part of your act.