A vampirically powered polyphonic synth!
The MIDIvampire-I is a 4-voice, polyphonic synth that is powered from the MIDI data line. So just plug in and play, no batteries required! There are 16 onboard wave tables to choose from, along with attack, decay, FM, AM, reverb, and other effects to shape the sounds to your liking. The output is 14b, 31.25ksps, so it doesn’t sound half bad for its size.
All of the documentation, including the MIDI implementation is up on the MIDIvamp Wiki. And, if you want to pick one up, swing by the store and have a look.