I guess I must have missed this the first time round. Nora the piano playing cat has had music composed to accompany her keyboard improvisations, and they sound gorgeous. She now has her own website (Nora the piano cat) As someone whose own cat has contributed to certain commercially available recordings in her own way (through using a MIDI control surface to cause program changes in software instruments), this is just my kind of site. Beats IRCAM anyday.