Run an alternating current through a coiled length of copper and you'll create a levitation cylinder. Drop a bar of aluminum in and you've got yourself some hovering metal. But leave the metal there too long...
The thing about this levitation cylinder is that it doubles as an induction heater. In a nutshell: the current coursing through the copper (which has been coiled to form a solenoid) creates an alternating magnetic field. The magnetic field induces a special form of electrical current (known as eddy currents) in the hovering piece of aluminum. These eddy currents give rise a phenomenon, called Joule heating, that, with enough power, can cause the metal to become very, very hot, as it does here.
Hands-on enthusiasts can find a very in-depth tutorial on how to make the coil like the one seen in the video, which operates at 1.6 kilowatts, here. Towards the end of the tutorial you'll find instructions on how to make a 10kW coil that can levitate and suspend molten copper and steel, which are denser than the aluminum in the video.