Micro-Macro, an animated short film that visualizes the nested scales of the physical universe (a la the Powers of Ten) using stop-motion-animated food. [more inside]
Powers of Ten is a classic film by Ray and Charles Eames which deals with the relative size of things in the Universe. (Previously) There are still six days left to join the Powers of Ten Video Response Competition, sponsored by the Eames Office and Core77, which already has some interesting entries... [more inside]
Nanoreisen. "A virtual discovery journey into the worlds of micro- and nano-cosmos." [flash] A kind of thematic followup to this.
The universe [flash]. I know, it's on a corporate site, and you have to sit through some pretentious Japanglish while it loads, but being able to use your mousewheel to scroll from femtometers up to the 100 billion lightyear scale is dazzling. I love cosmic zooms. Remember to pray that there's intelligent life in space, because there's bugger-all down here on Earth, except for folks like Metafilter's own kokogiak, who shows us everything in the solar system bigger than 200 miles in diameter.