I hesitated to blog about Gapminder earlier when it occurred to me that many of you might already know about it, but I was shocked (shocked!) when an acquaintance of mine said that Gapminder was "fun for ten minutes." (I forget her exact words.) There's more here than one would suspect from first glance. I recommend watching this demonstration by Hans Rosling, "professor of international health at Sweden's Karolinska Institute, and founder of Gapminder, a nonprofit that brings vital global data to life."
Here’s a link to Gapminder. The site features tutorials.
Addendum: Happyjuggler0's comments to this post make me think that I probably should have also provided a direct link to the new Gapminder Beta (which can also be found near the top of my last link). The tutorial for Gapminder Beta is in the top left corner ("help"). I'm really looking forward to being able to import data into this. What a great tool!