Usually we see Kinect hacks with a single Kinect camera. Oliver Kreylos changed this and added a second Kinect to his hack! Having both modules in 90 degrees, he managed to render them in one single image on the PC, and thus he produced a 3D representation of an object, that he can rotate without rotating the cameras themselves! He had predicted that the IR beam of one module would interfere to the other IR receiver, which actually did happen. This is obvious when only the video from one camera is rendered. But when the two signals are merged to one, the images complete each-other, and the result is very good. Visit his website for more.