Last week I took a quick trip out to Portland, OR and did a bunch of shopping. One of the places I stopped by was Control Voltage, a small storefront that sells various synthesizers and other electronic audio gear. They had a bunch of DIY kits, and I picked up the Bleep Drum kit because it looked interesting.
The heart of the system is an ATmega328 with some custom Arduino sketch code that does some basic drum functions, along with a couple of extra noise settings. The full schematic and source code is available at the Bleep Labs site, though with the kit you do get a pretty nice custom board and stand for the circuit.
I'm continuing to work on some audio circuits; along with the drum circuit I've also made the Vibrati Punk Console and the Bazz Fuss effects pedal circuit for Amy's bass. My circuit building continues as I work through some of the other items on the Home Wrecker and Runoff Groove sites.