Synthgeek has released SG-Modutron Mini, a free software synthesizer for Windows that based on "virtual circuit-bending":
The initial idea started out as an attempt at making a bass synth version of the APC synth. It turned out to be impossible to get it to track pitch at all, so more experimentation ensued, and this is the result. It does track pitch, but often sounds will change across the keyboard or possibly even stop making sound at a certain key.
Pricing and Availability
SG-Modutron Mini is available now as a free download.