A lot of names have been seen on the web for the object : Arc, Gem, Sphere. But the official name is Playstation Move. This accessory allow movement detection for the PS3 and was officially shown at GDC2010. This device is a response of Sony over the Microsoft Natal and Nintendo Wii Mote.
Here some videos show the device at work :
The guy that play at the FPS seems quite boring experience.. It do not move at all.. No immersion inside the action... What novelties beside a classic gamepad ?
The following video is clearly more fun : A real interaction is visible ( over the ball detection and sensor reactivity)
And more interesting the player smile... that it's share a good user experience.
On some video on the web we can see two "Move" pad on the hand player that show that the used camera can track different Light Ball so different "Move" device.