Wii Vitality Sensor (TBA)

Announced though not demonstrated at this year's E3 show in Los Angeles, little is known about what Nintendo plans to do with this odd peripheral.

The "vitality sensor," as Nintendo calls it, is actually a pulse oximeter, which can measure things like heartbeat and how much oxygen is in your blood. All Nintendo has said about this console add-on is that it will "initially sense the user's pulse and a number of other signals being transmitted by their bodies, and will then provide information to the users about the body's inner world."

For developers, the gadget could be a boon. The capability to track a gamer's excitement in real time could help developers change the pace or delivery of in-game moments, making each gaming experience custom-tailored to the person playing it. Still, it could ultimately end up being simply an easy way for Nintendo to make money on people who want to check their pulse in games like Wii Fit.