HubbleSite -- Out of the ordinary...out of this world.
Today some reaaaaaally old history! Actually, I'm not finding the really cool interactive I first found at this site. But there's still lots here. Many of the interactives are in the Amazing Space section, including this cool history of telescopes.Some of these start as HTML pages, but keep digging. There are Flash, Php, and Quicktime interactives burried here and in the rest of the site.