Red Light, Green Light features one person as the Red Light, who faces away from the others. The Red Light calls out "green light!" allowing the others to move closer, but the Red Light can call "red light!" at any point and turn around. If anybody is caught moving after Red Light turns around, they are out.
What you may not realize:
Red Light, Green Light is where kids got the idea that it was alright to tell other kids to go play in traffic.