Polpotronics creates new fun open hardware things for old computers. It's run by Ian "polpo" Scott.

PicoGUS - hardware emulator of ISA sound cards and CD-ROM for retro PCs
PicoIDE - hardware emulator of ATAPI CD-ROM and IDE hard drives
ImageScribbler LocalSquawk Option - reverse engineered LocalTalk adapter for Apple ImageWriter II and LQ printers