The SwinSID is a pin-compatible and software-compatible replacement for the Commodore SID chip based upon an Atmega microcontroller. You can drop this chip right into a socket on the motherboard of a damaged Commodore computer, or you can probably drop it into a hardware synth that uses SID chips and hit the ground running. The firmware image and schematics are available for download for free on the website, so you can roll as many of your own as you want.