Explore World Data with Factbook eXplorer from OECD
The Organization for Economic Co-operation and Development (OECD) makes a lot of world indicators available (e.g. world population and birth rate). Much of it goes unnoticed, because most people just see a bunch of numbers. However, the Factbook eXplorer from the OECD, in collaboration with the National Center for Visual Analytics, is a visualization tool that helps you see and explore the data.
Those who have seen Hans Rosling's Gapminder presentations - and I imagine most of us have - will recognize the style with a play button and a motion graph in sync with parallel coordinates and a map. Choose an indicator, or several of them, press play, and watch the visualization move through time.
Also, if you've got your own data, you can load that too, which is certainly a nice touch.