I admit, I haven't tried this website, but the concept behind it is very interesting. I could see how some kids could really get into this website. Basically, kids create a nation and build it and try to become the best nation overall. Sort of like a multi-layered game of "Risk" played online in a social setting. Lots of government and social studies learning possible. Might be something you try out this summer and play around with if you are a social studies teacher.
NationStates website click here!