Skinput – Allowing skin to be used as an input device
This has been around for over a year, but is still pretty awesome.
They are ussing the human body for acoustic transmission and gestures to control user interfaces and games.
http://research.microsoft.com/en-us/um/redmond/groups/cue/publications/HarrisonSkinputCHI2010.pdf
by Chris Steinmetz on February 22, 2011