Empire – a simulation of a full-scale war between two emperors, the computer and you. Naturally, there is only room for one, so the object of the game is to destroy the other. The computer plays by the same rules that you do. This game was ancestral to all later expand/explore/exploit/exterminate games, including Civilization and Master of Orion.
This code originated under VMS but has been forward-ported to modern ANSI C. It is known to run not only on Linux but also under Windows and Mac OS X; all you need is a local port of the curses library.
The ancestral code was by Chuck Simmons. Since around 1990 it has been maintained by Eric S. Raymond.