Thanks to TidBITs for the introduction to LEMUR:
LEMUR is a Brooklyn-based group of artists and technologists
developing robotic musical instruments. Founded in 2000 by
musician and engineer Eric Singer, LEMUR’s philosophy is to
build robotic instruments that “play themselves.” In LEMUR
designs, the robots are the instruments.
There are a couple of movies of the GuitarBot in action and an MP3 of a GuitarBot composition available on their AV page.