Moving visualisations of air traffic patterns.
If you've watched television for any length of time, chances are you've seen the classic FAA blips-on-a-screen representations of air traffic over the United States. A student at UCLA has taken this to the next level by generating high-res 3d movies of air traffic over the country. They're all in QuickTime format, so you'll have to have the appropriate CODECs or players installed. The animations are an interesting diversion, if nothing else. There is a version where each kind of flight is colour-coded, a 3D dome projection (nice work on that, incidentally), and even one where an amorphous blob is generated by all of the traffic.