Freeciv is an open source, multiplayer and completely free empire-building TBS (Turn-based Strategy) game where players become leaders of various civilizations. The gameplay is very similar with the one of the Civilization I & II games.
It’s heavily inspired by the history of human civilization
Being heavily inspired by the history of human civilization, the Freeciv game commences in prehistory. The player's mission is to lead a tribe formed from as many people as possible from the Stone Age to the Space Age.
How to play Freeciv in multiplayer mode
To start a multiplayer game, type "civclient" in a shell prompt (without quotes). It is recommended to use the “civclient -tiles trident" command to get a 2D map. Click “Connect to Network Game” on the main menu, click the "Metaserver" tab and then the "Refresh" button.
See if a game is available on the "Pregame" window, if possible one that has players, connect to it and wait there for more players. Available commands are "/create name" to add an AI (Artificial Intelligence) client and "/start" to begin a new game session.
It is more than a game
Freeciv is more than a game, as it allows users to make they own rules. It features support for up to 126 players, support for computer-controlled players, as well as multiplayer (TCP/IP) support via LAN (Local Area Network) or the Internet.
Supports over 500 nations and multiple languages
The game supports over 500 nations, more than 50 playable units, multiple languages and modpacks. It comes pre-loaded with scenarios, maps and an in-game help system that will help new users to learn how to play Freeciv.
Supports a wide range of platforms
Freecive is a multi-platform game supported on GNU/Linux, BSD, Solaris, SunOS, OS/2, Mac OS X, Microsoft Windows, SGI Irix, IBM AIX, HP/UX, QNX, OpenVMS, OSF1, Cygwin and Maemo platforms. it is written entirely in the C programming language.