ofxKinect is an Open Frameworks addon for the Xbox Kinect that runs on Linux and OS X. Dive into some code below:

ofxKinect
https://github.com/ofTheo/ofxKinect

ofxBox2d, ofxFileStream, and ofxTimer
http://code.google.com/p/vanderlin/

ofxKinect_Box2D
https://github.com/jvcleave/ofxKinect_Box2D