From Gizmodo: Musically inclined hackers too lazy to play drums themselves need to check out this amazing "Yellow Drum Machine". The robot basically wanders around searching for "playable" surfaces, then creates and combines samples on the fly into rhythms. Possibly the coolest feature is that when it hears your stomping or clapping, it joins in after measuring the speed for four beats.

I switched to a worse video because the old one seemed unavailable all the time.