FreeCiv is an open source, turn-based strategy game inspired by the history of human civilization. Players control a civilization, beginning in 4000 B.C. and advancing to the near future. The game features a variety of real-world resources, units, and technologies that players can use to expand their empires. Players must manage the development of their civilization by making decisions about which technologies to research, which units to build, and how to allocate resources. Players can also interact with other civilizations in a variety of ways, such as trading resources or engaging in diplomatic negotiations. FreeCiv is a highly-addictive game that will keep you engaged for hours.
Discontinued You can still buy this game at GOG.com