iRobot (the makers of the Roomba robotic vacuum cleaner) are developing an anti-sniper robot. According to the article,

When REDOWL's microphones detect a gunshot, the device calculates the source of the sound, swivels the camera, illuminates the target with either visible or infrared light, and uses a laser to calculate the range...

"You'll actually see the sniper before the smoke disappears from the shot," said Joe Dyer, iRobot's executive vice president and general manager.

The system is not configured to fire back automatically -- this still requires positive human intervention. (Via /.)