When I was home over Winter break last year a friend of mine was working on this project for kickstarter:
Specdrums is a drum machine and synthesizer that you wear like a ring on your finger. Depending on what color you tap with the device, a different drum sound will be produced. Your cell phone can synthesize different sounds and the device works on any surface. It can pick up the colors of your clothes so you can play body music.
What I admire about this project is how playful it is. A lot of new technology like this is very intimidating to use but this seems almost childish and fun.
I was lucky enough to see these guys working on this project and see the mechanisms on the inside of the test product.