Satoru Iwata just announced the latest health-related peripheral for the Nintendo Wii -- the Wii Vitality Sensor. We're still extremely confused as to the purpose of the device, or how it will be implemented in a game, but here's a brief breakdown: It's a biorythm sensor that connects to your finger and transmits your heart rate to the Wii. How will that be used in gameplay? Will it make an appearance in Wii Fit Plus? We just don't know.