I'm visiting Ubud again this June (last time was in 2008). I was asked to bring my sax to sit in with some bands. Will I have any problems getting through customs with my instrument?
I can't see why you would have a problem, I don't think there's any regulation against bringing muscial instruments to Indonesia.
Give a man a fish and he will eat for a day. Teach a man to fish and he will sit in a boat drinking beer all day.