The North American Aerospace Defense Command (NORAD) is a United States and Canada bi-national organization which defends the homeland through aerospace warning, aerospace control, and maritime warning for North America. Aerospace warning includes the monitoring of man-made objects in space, and the detection, validation, and warning of attack against North America whether by aircraft, missiles, or space vehicles, through mutual support arrangements with other commands"
Also, on every Christmas Eve since 1955, the folks at NORAD have been tracking Santa's sleigh as he makes his way around the world delivering presents.
Enjoy the live tracker above, courtesy NORAD.