Do you feel like you're being watched? Unless you're visiting the home of Instructables member jgbradley1, then you probably are.
It's a classic horror trope in movies and television: as you move through a spooky room, the eyes of a picture seem to follow you around. jgbradley1 made that real with a Kinect sensor input and a poster of the cover of Batman: Legends of the Dark Knight #50. He painted wood balls to serve as eyeballs and placed them on rotary servo motors. You can find his circuit diagram and code here.