AirPiano - Indulge Your Inner Beethoven

Remember playing air guitar to your favorite tunes? How about an air piano. Except this one really works. From the maker's website:

The AirPiano is an innovative musical interface which allows playing and controlling software instruments simply by moving hands in the air.

Above the AirPiano is a virtual matrix of keys and faders, each assigned with MIDI messages and ready to be triggered. The length of a triggered note is equivalent to the time a hand is placed on the corresponding virtual key. This is also confirmed by LED feedback.

Neat.