Here are the Hamsters! A graduate student at Cornell University built a MIDI sequencer controlled by six hamsters:
"The MIDI sequencer intelligently produced melodies by manipulating the musical elements of rhythm and note-choice. Guided by inputs based on hamster movements, Markov chains were used to perform such beat and note computations. In culmination, 3 simultaneous voices were produced spanning 3 octaves and 3 rhythmic tiers. Each voice was controlled by two hamsters: one that was responsible for adjusting the rhythmic qualities of the melody and another that modified the note sequence. With all of these elements in combination, an output was produced with very musical qualities."
Link (Thanks, Nick and Morris!)