You start the effect using three small brass cylinders.
Place a small rod in one of the containers, screw the cap back on, then shake it to hear the rattling sound.
You then visibly switch the three containers around, just like the classic Three Shell Game, and ask your spectator to find the container with the rod.
No matter how quickly or slowly the containers are mixed, the spectator is never successful in finding the container that rattles, even if the container is marked!
Though it sounds impossible, it is very, very easy to do.
You are always in complete control of whether a tube rattles, or doesn't.
This can be played as a straight magical mystery, or can be built into an excellent comedy routine.