Privateer: Ascii Sector is a 100% free space combat/exploration/trading game for Windows, Mac OS X and Linux. You start with a simple spaceship and can then accept missions or trade goods to earn enough money to upgrade your ship or buy a new one. The game offers a wide variety of missions, commodities and ships -- a lot more than the original Wing Commander: Privateer, on which this game is based.
You can engage in deadly fights both in space and on the ground, and using the Privateer: Ascii Sector quest language, you can create your own stories in the Ascii Sector universe, or have fun with other players' stories.
What sets this game apart from most others is its 'graphics'. Privateer: Ascii Sector uses only ASCII characters in 16 different colors to present its environments. This might take some getting used to for most players, but it also means that the game's single designer and programmer can concentrate on gameplay instead of fancy graphics. Check out the screenshots to see how the game looks.