I recently organised a Royal Musical Association Music Philosophy Study Group workshop on philosophy of human+computer music, held here at the University of Sheffield. We had keynotes in the morning, then a whole afternoon of discussion with live music. Further details of what we were trying to achieve can be found here.
It seemed to go very well (at least the bits that I saw between running around organising sustenance for our guests). I hope that this will turn out to be the first of a whole series of similar events.