At E3 yesterday, Nintendo unveiled the 'Wii Fit Plus', an add-on that wraps around the finger to takes the player's pulse. Obtaining a players pulse while also having the players weight, will give Nintendo the ability to calculate calories burned. 
While Nintendo did not show any games or announced any specific uses for the new add-on, only our imaginations can tell us what the new add-on could be used for. Nintendo President Satoru Iwata said that the Wii Vitality Sensor is "another entirely different way of thinking about games".
"Traditionally, video games have been used to create excitement, but it may not be long before games help people unwind or even fall asleep," he went on to say.
Even with the new Wii Vitality Sensor for the Wii Console being announced, I don't think the excitement of it compares anyway to the excitement that was taking place over at the Microsoft press conference where they unveiled the 3D Motion Sensing, controller-free, Camera device which tracks your movement without holding a controller or device.
The console wars are just beginning to heat up and I look for some interesting innovations to be revealed in 2010.