GraphJam is like the Facebook of data representation. People create graphs, and other people come on by and like them. Or not.
Have your students create graphs on the site. They can make circle, bar, and line graphs, as well as Venn Diagrams. Let them be creative.
Warning: The site isn’t targeted at educators. Some of the graphs that people submit could be considered inappropriate in some schools and some grade levels. Unfortunately, they are some of the funniest ones, too.