According to an IGN article here, an early version of the DualShock controller for the much anticipated Playstation 4 measured how much the player was sweating. Yes, sweating. It simply measured how wet your hands were.
As mind-bendingly useful as this feature no doubt would have been, the project was abandoned after a test with Patrick Ewing resulted in an overloaded controller blowing up.
The PS4 is due out this fall.