Designed by Dr. Jim Levine of the Mayo clinic, the Gruve is a wearable device that measures calories burned throughout the day. If you have been sedentary too long, it lets you know it.
By keeping track of all your daily movements / calories burned and comparing those numbers to a predetermined goal, the user should be able to keep their metabolism running like a well-oiled machine. The fact that it vibrates and lights up red when you are being lazy also adds a bit of incentive.
I'm not sure if Gruve will ever become a real-world product, but it is definitely a good idea. Even if you are already fit, this could prove extremely useful. Personally, I would use something like this in the gym to keep the appropriate pace and level of intensity during a circuit program. [Worrell via Core77 via DVICE]