Miniature Wii sensor bar. I ended up moving it below the monitor, since you hold your Wiimotes below eye level, and the Wiimotes weren't built for being held so close to the monitor (so keeping the monitor at eye level and Wiimote at arm level would position the sensor bar out of the camera's field of view). The cable now gets in the way of the front-panel controls, but it's the price you pay for playing Wii games on a 17" VGA.