This thing is amazing. I just read this in the online version of the IEEE Spectrum. Omer Yosha, the inventor, has invented an air piano. Wonder what is an air piano. It basically is a piece of wood and a sheet of plexiglass. He has some sensors which detect his hand at three different levels, and plays different notes accordingly.
A note about Yosha:
Omer Yosha is a formally trained musician who plays guitar and sings. He left his home near Tel Aviv to see the world, traveling dusty paths in India and busking in the streets of London before settling in Berlin. The German capital is wide open, its energetic art and design scene spurred by a polyglot, multidisciplinary mix-and-match mind-set and cheap space. — IEEE Spectrum
There is a video in the above link – which is awesome.
I found one more video that I found on youtube.