From the MAKE Flickr photo pool
The elegantly compact aurora “Open Source DJ Mixer” can be used in conjunction with MIDI software via MAX/MSP or PD and features a tasty LED lightshow capability -aurora is a usb powered multichannel mixer in a typical dj form factor. the device features two linear channel faders, a single a/b crossfader and eight backlit buttons. twenty four backlit knobs allow you to control effects. aurora, unlike most midi controllers, enhances performances with controllable ambient lighting. aurora easily integrates with your favorite midi compatible software.
The hardware is planned to be released in fully assembled and kit versions – no word on pricing as of yet.
Source code schematics and specs – aurora open source mixer