Swedish inventor and musician, Martin Molin has created the mind-bending Wintergatan Marble Machine, a complex Rube Goldberg machine that synchronizes 2000 falling marbles to play various instruments. The instrument contains a full xylophone, various drums and even a Hofner Beatle Bass. A complex series of pegs on a wheel releases the marbles according to Molin's tedius programming. (The concept is very similar to a simple musicbox...except a lot cooler!)
Notice how Molin keeps the machine running while still playing the bass with his left hand!
Molin has documented the building process in a series of videos on his website.
Hahaha. Love this thing. Yeah the guy is far out.
Way cool. Except those aren't marbles, they're ball bearings. Except the black one(s) (which may be a painted ball bearing).