I was part of the core design team that was responsible for developing The Intel® Skeletal Hand Tracking Library, made available for free public release in May 2013. As it says on Intel website:
The Skeletal Hand Tracking library is designed to track the 3D pose of the user’s hand based on depth data from the Intel® Perceptual Computing SDK on a system with a Creative Interactive Gesture Camera™. In each frame, the library provides the full 6-DOF position and orientation of 17 bones of the hand; this data is suitable for enabling physically-based or similar interactions within a virtual 3D environment. The Skeletal Hand Tracking library is accessible through a simple C API, with supporting C++ code to facilitate quick application integration. Additional samples are also provided to demonstrate the technology and its usage.