Aurora is an awesome open source usb powered multichannel mixer in a typical DJ form factor. Aurora is designed to easily integrate with your favorite midi compatible software.
The device features two linear channel faders, a single a/b crossfader and eight backlit buttons.T wenty four backlit knobs allow you to control effects.
Aurora, unlike most midi controllers, also looks pretty awesome, with controllable ambient lighting.
Here’s a video of the Aurora mixer in use:
Details, including source code, Gerber files, manuals and more, are available at the Aurora site.