Space Empires III

A 4X strategy that will remind you of Civilization, Master of Orion, and other strategy games. The game was produced as low budget shareware, but has developed a cult following.

You control a planet in the solar system, make decisions about research, design your ships how you want, and make diplomatic choices. It offers PBEM capability, but is rather time consuming. Other than that, there is hotseat multiplayer.