Photograph of jumping rings

Apparatus:
Base with coils, 2 core extensions, 3 solid metal rings, 1 metal ring with a slot in it, liquid N2 and tongs.

Description:
Plug in the base to a wall outlet. Put rings around the core of the coil, and flip a switch. One of the 2 switches toggles between one and 2 coils, the other is power.
The solid rings will jump as eddy current is induced, the split ring will not budge. The core extensions, when stacked one atop the other on the core, extend the magnetic field, which results in the rings jumping higher. The rings will almost reach the ceiling if they are cooled in liquid nitrogen.
When doing this, be careful. The metal rings are quite cold.