I attended the Handmade Music event here in Austin. It was the fourth one they did. I found it by searching online for "circuit bending event Austin." I figured in a town this cool, there must be some circuit bending event going on – and there is. This was the fourth event and they are doing them every month. It is run by Dr. Bleep of Bleep Labs. They are the people who make the Thinkgamagoop sound machine that is sold through ThinkGeek.com among other places.
We built two devices during the event. One was the SimSam from 4MS. The other was the Nebulaphone from Bleep Labs - which isn't even publicly available yet.
The event was a blast and I will certainly go to the next one. If you are near Austin, I recommend attending. I wore my APC shirt to the event and a lot of people commented on it. Now I am seriously thinking of selling them.