NORAD tracks Santa.
Back when I was in the radar biz we used to do this sort of thing locally, for the families of the guys at the radar sites where I was stationed. Back in the day every radar site had a video mapping device that fed programmed exercise video to Operations; the normal output from the video mapper was "canned" and consisted of video blips simulating actual aircraft. On Christmas Eve we'd load up a special video overlay and route it to the intercept control scopes in Operations. While "exercise" video consisted of fake bogeys (simple blips) and tracks to train intercept controllers and technicians, the special Santa video showed a sleigh and reindeer on the scopes. Not nearly real, but real enough for the kids that saw it!
The kids always got a big thrill out of the radar displays. Doing the Santa video was one of the most fun things I ever did while I was a radar guy.
Updated on 12/25/2005 0215: correct typos and grammar plus add a small amount of content. I shouldn't post after I've been into the egg nog!