Google Public Data Explorer
Google’s Public Data Explorer is a great, free resource for students and teachers interested in data science and statistics.
The site allows you to create custom graphs of available data sets, making it easy to experiment with different representations and explore the meaning of data.
There are several data sets available to play around with. The OECD Factbook alone provides a wealth of raw data on education, energy, employment, population and migration, and many other categories. There are also data sets available from the U.S. Census and the U.S. Bureau of Economic Analysis. There appears to be support for using your own data sets, as well.
The data can be represented in a variety of ways: histograms, line graphs, and even dynamic time series are all available. It’s a great way to play around with data, and to build skill and intuition in data analysis, interpretation, and representation.