Microsoft has had a patent application for a "wearable electromyography-based controller" approved by the U.S. Patent Office (via Engadget). In layman's terms, the tech involves wearing a device that senses muscle movement and then communicates that data to whichever computer (or game console?) it's connected to.
The patent request was first filed back in 2010, at a time when Kinect was still known as "Project Natal." It's technology that could be adapted in any number of ways, from sensor nodes that you stick to your body to articles of clothing. It's still hard to say what the gaming applications might be, but I think Jake had it right back in 2010: Air Guitar Hero.