Ok, this just appeared on Slashdot, but it's cool enough that it warrants a repost.
Powers of ten.
It's a little animation thing that starts with an image of the universe (or rather, outer space, showing a bunch of galactic clusters and stuff), then starts zooming in, eventually focusing on the Earth, and keeps on going until it shows matter at the subatomic level. It's amazing how quickly you go from the super-macroscopic to the super-microscopic.
Yeah. Much coolness.