Wikipedia Flu Time-lapse
Here's something interesting I saw on Wikipedia. There is a map of the US with states colored according to the spread of the H1N1 flu epidemic. Take a look: H1N1_USA_Map.svg. The interesting part is actually at the bottom of that image page.
Wikipedia, being a wiki, versions everything. It has to. No one actually changes a page, they just add a new version that is a derivative of the "current" version. Because of this, Wikipedia has incidentally created a time-lapse version of the map in its version control system. In case you can't see it when you are reading this, here's what part of it looks like,
That's the timestamp and the state of the spread at that time, presented in an extremely useful way. And this was created by accident. Pretty cool, eh?