A fun online game where teachers (or students) could create a board filled with various vocabulary words or concepts. The goal is to connect the terms in groups of four based upon a common idea (which the creator determines).
Check out this online collection of constitutions from around the world. Constitutional reform happens all the time, and the concepts of collaboration, discussion and debate are vital to the process. Students can compare constitutions, import sections from various constitutions to GoogleDocs to collaborate with peers and discuss reform.