Flux pinning of an EBCO (type II) superconductor and NdFeb magnets.
This is possible because of how superconductors react to magnetic flux lines. When the s.c. enters its superconducting state it expels all magnetic field lines and so levitates above a magnet. But in a type II s.c., at higher temperatures the magnetic flux is allowed to enter in quantized packets.
If one then brings the s.c. to lower temperatures these flux packets are pinned in position and cannot be moved in or out. So the s.c. will not only levitate above the magnet, but below!
Thanks to stemgrrl for inspiring this post.