Valve is traditionally a company that tries new things. Ben Krasnow, an engineer working for the software company, has taken that policy a bit further. He has built two experimental inputs for a computer: one for your bum, and one for your tongue. Thankfully, they are not the same device.
One controller uses the persons body posture to turn left and right, or move forward and back. It’s effectively a modified bathroom scale, and works amazingly well for something requiring you to lean back and forth. Although Krasnow admits that there are issues when trying to turn 180 degrees.
The tongue controller combines a brace retainer with an optical mouse. This is the ultimate use of hands free controls, but isn’t accurate enough for every day use. It will definitely prevent anyone from borrowing your mouse ever again.