NationStates is a nation simulation game that allows you to create your own country with your own politics and ideas and then care for its people, "or oppress them".
You can also interact with other countries, participate in a type of united nations, and run your country as you see fit. There is a news and forum section also to share and get ideas and information.
This is a great way for students to really explore politics and government.
Here's a spotlight page on one of the countries.