In the video below, you'll find a pretty rocking DJ set thanks to an iPad and some other pretty gnarly hardware. This isn't exactly a DIY solution, since DJ Kutski is using Traktor Pro (that's the software on the screen above) and an X1 controller, both of which are pretty significant pieces of DJ gear. But the iPad is definitely a big part of the equation, and it's running TouchOSC, a neat app that allows you to hook up sound interfaces over Wi-Fi using some very configurable abstract graphics.
There's not much in the way of explanation. You can definitely see him changing pitches and adjusting the volume in real-time (pretty impressive just running the controller over Wi-Fi), but non-DJs will probably have to look elsewhere to figure out exactly what's happening here. Then again, if nothing else, you can enjoy some nice iPad-driven beats on this Christmas Eve. Enjoy!