Although any electromagnetic force could be used to counteract gravity, magnetic levitation is the most common. Diamagnetic materials are commonly used for demonstration purposes. In this case the returning force appears from the interaction with the screening currents.
For example, a superconducting sample, which can be considered either as a perfect diamagnet or an ideally hard superconductor, easily levitates in an ambient external magnetic field. The superconductor is first heated strongly, then cooled with liquid nitrogen to levitate on top of a diamagnet. In very strong magnetic field, by means of diamagnetic levitation even small live animals have been levitated.
It is possible to levitate pyrolytic graphite by placing thin squares of it above four cube magnets with the north poles forming one diagonal and south poles forming the other diagonal.
Magnetic levitation is in development for use for transportation systems. For example the Maglev transportation includes trains that are levitated by a very large number of magnets and, due to the lack of friction on guide rails, they are potentially faster, quieter and smoother than wheeled mass transit systems.