Freeciv is a multiuser reimplementation for Unix/X of the famous Microprose game of Civilization. By default, the game is an improved Civ II, but this can be customized; modpacks for near-100% compatibility with Civ I and Civ II are included. Multiuser gameplay is real-time: in each turn, all human players move concurrently. The game is designed to remain fairly playable even on poor network connections. Freeciv can also be played on standalone machines, and its AI players are a good challenge for beginners. The source code comes with the server, two X clients, and non-X clients for MS Windows and Amiga. Freeciv is released under the GNU General Public License. It is maintained by an international team of coders and enthusiasts, and is easily one of the most fun and addictive network games out there.
TripleA is a clone of the popular board game "Axis & Allies", which is a turn based strategy wargame. TripleA also acts as a game engine allowing creation of custom games with similar mechanics to Axis and Allies. It supports online play, network play, play-by-email, and single player vs AI or hot-seat. It comes with 11 different maps and the option to download more from online repositories. Most games take place during World War II, though there are mods to play other conflicts like the Napoleonic wars, or Lord of the Rings.
Scorched 3D is a modernization of the classic DOS game Scorched Earth ("The Mother Of All Games"). It incorporates a lively three dimensional landscape that includes animated jets, naval vessels, water, and even birds, in addition to detailed tanks and projectiles. Other enhancements include LAN and Internet play and music.
Atanks is a multi-platform Scorched Earth clone similar to the Worms series of games. Annihilate the other tanks to earn money, then spend it on bigger and better shields and weapons to wipe out the opposition. It features a wide array of weapons, AI players, destructible landscape, weather, parachutes, teleports and a wide range of other features.