another random user tips this quote from the BBC:
"A wrist-worn sensor that creates 3D-models of the user's hand movements in real-time has been built by Microsoft. The Digits prototype is part of an effort to create a mobile device that would allow its owner to control a range of equipment using hand gestures. The firm said it could be used as a virtual TV control, a way to operate a smartphone while it is in the user's pocket, and to play video games. It is designed to be less cumbersome and uncomfortable than sensor gloves. However, some experts question whether consumers would want to wear such a device during their day-to-day activities."
ACM has the research paper
(PDF) describing this device and its use.