I saw this on Digg (http://www.digg.com) today:
http://learn.genetics.utah.edu/content/begin/cells/scale/ It reminds me of that old video they used to show when I was a kid
that zooms from the galaxy down to the earth, into someone's back
garden then into the really small stuff. Very nicely done overall,
just slide the slider under the picture to zoom. It uses the (evil)
Flash, but it's quite fun to play with nevertheless.