Visualizing Data with Gapminder

This remarkable website, Gapminder, developed in Sweden allows you to visualize data "some 500 indicators (relating to health, income, education, energy, the environment, technology, and more.)" from such standard sources as the United Nations, World Bank, and OECD. Watch this 4 minute video to get a sense of what it can do. http://www.gapminder.org/videos/200-years-that-changed-the-world-bbc/
There is definitely a learning curve (here is a page with a 2.5 minute tutorial to get started) but it's a rich resource for teaching and presenting the possibilities of data.