When I last taught social studies, I used the game Real Lives (http://www.educationalsimulations.com/). It allowed students to actually walk in the shoes of a person in a different culture. We simply used the free trial where students got to try three lives. It was great for days before Spring Break or when we have continuous interruptions due to snow delays and cancellations and one class gets ahead of another.
This game was originally part of Games for Change (http://www.gamesfoechange.org/). Each year, this website showcases a series of educational games. It might be fun to browse through several of these games during your "free time" to see how you could use it in your class or curriculum. Quickly browsing this year's list, here are a few I though many of you could use: Inside the Haiti Earthquake, Crown or Colony, Republica Time (how to influence public opinion), Fibber (Election of 2012), and Depression Quest to name a few.
These games could illustrate a concept that you are trying to teach and then you can create student activities that reflect on what they learned. Or you could use the game simulation as a prompt for an assignment or essay. By using a game you are naturally tying into an interest of many students. My students were drawn into the games and wanted to play them on their own- while at the same time teaching them invaluable skills and knowledge that they were not getting from traditional teaching alone.