Civilization (full name Sid Meier's Civilization) is a series of games in which one goes out to settle cities and manage a nation based on real life ones (usually like an empire, or a certain country). It's an older series, but they're wildly popular games and have a growing community. I've only played Civ V so far (it was on a Humble Bundle sale), but it's pretty interesting I think. I like how all of a sudden, you're just sitting there being peaceful until a bunch of nations declare war on you, even if you haven't done anything to them. Though sometimes, I like to be fun and declare war on everyone and watch my empire go into utter chaos. It's pretty fun when they do that! I'm looking forward to playing the others now! :)