[youtube=http://www.youtube.com/watch?v=WLWAWtpcelM]
[kero905] sent in this project he’s working on. It is an open source hardware converter to connect Wii controllers via USB. It uses an Arduino for its brains. It is still in development, the only controllers that work are the nunchuck and the classic. He notes that there are enough extra pins left to adapt to an arcade controller fairly easily. The code is available on the site, as well as a rough parts list.