Philipp Lenssen blogs about a tool called Gapminder that can be used as a subscribed link or by interacting with the graph directly. This tool helps you "make sense of the world by having fun with statistics". From the tutorial page:
What you see is a scatterplot where each bubble represents a country. The position of the bubble is determined by the indicators on the axes. The default indicators are income and life expectancy. The indicators can be changed by clicking on their names and selecting a new indicator from the list. The size of the bubble represents the population of the country. The color represents the country's geographic region by default, but it can be changed to show indebtness or income group instead. To see what a certain color means, move the mouse over the colored boxes to the right of the chart.