The Roomba has a piezo beeper that can play tunes. YouÃ¯¿½ve heard it. And its motors make noise. Why not put them under MIDI control. So here is RoombaMidi: a Mac OS X application that creates a virtual MIDI instrument for use by any Mac OS X MIDI sequencer, like Ableton Live, Logic, and so on.
If you donÃ¯¿½t have a sequencer or just want to play with this quickly, grab the awesome and free app
MidiKeys. ItÃ¯¿½s a little virtual MIDI keyboard.