MKinect and MKinectUIExtensions are being provided under LGPL!
To see MKinect and MKinectUIExtensions in action watch this video: http://screencast.com/t/wy6ndBGvS (the project is called "GestureRun")

This project was built ontop of the Open NI platform. I used the following drivers and executables:
(OpenNI unstable) http://www.openni.org/downloadfiles/openni-binaries/20-latest-unstable
(SensorKinect) https://github.com/avin2/SensorKinect
(PrimeSense NITE) http://www.openni.org/downloadfiles/openni-compliant-middleware-binaries/stable/55-primesense-nite-beta-build-for-windows-v1-3-0
PrimeSense Key: "0KOIk2JeIBYClPWVnMoRKn5cdY4="

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Manuel Naujoks