Microsoft's Skinput turns hands, arms into buttons - CNN.com

http://edition.cnn.com/2010/TECH/04/19/microsoft.skinput/index.html?hpt=C2

This is similar to MIT's Six Sense project and is showing how we might
be using technology in the future. The Six Sense project used a person's
palm rather than their arm which might make a bit more sense.

This is the Microsoft page on their technology
http://research.microsoft.com/en-us/um/redmond/groups/cue/skinput/

And a link to an award winning paper.
http://research.microsoft.com/en-us/um/redmond/groups/cue/publications/HarrisonSkinputCHI2010.pdf
Chris Harrison, Desney S Tan, Dan Morris
Proceedings of ACM CHI 2010 (Best paper award)