Vassal is a game engine for building and playing online adaptations of board games and card games. Play live on the Internet or by email. Vassal runs on all platforms, and is free, open-source software. This software requires java to run.
UFO2000 is free and opensource turn based tactical squad simulation multiplayer game. It is heavily inspired by the famous X-COM: UFO Defense game. While UFO2000 engine was specifically designed to be compatible with the graphics resources and maps from X-COM, you don’t need any proprietary data files to play as a new fan-made set of graphics exists and is included in UFO2000 distribution by default, so the game is ready to run out of the box.
UPDATE: There is a new version of the game. Download it from the official site.
LordsAWar! is a free, turn-based strategy game where up to 8 players strive for control of as many cities as possible. Produce new armies in cities to conquer nearby cities. Using the income from those cities, make more armies to take more cities. Send a hero to a temple to get a quest, or maybe search a nearby ruin instead. Play with others or against the computer.
Salem is a fully open sandbox MMO with deep crafting elements.
Salem is set in a fantastical New England and offers free form massively multiplayer gameplay in a persistent, mutable and online world. With players taking the roles of intrepid colonists from the Old World seeking to make lives for themselves in the New, Salem provides them with unique crafting, farming and building systems inspired by 17th century alchemy. For Windows, OS X, Linux.
UnReal World is now donationware (free to download and play with the possivbility to make a donation to the author)
UnReal World, or UrW, is a unique graphical roguelike RPG taking place in the Far North long, long ago. It brings you a realistic game world rich with historical atmosphere in which northern folklore, knowledge and way of life play an important part. The atmosphere and game features are highly original and compelling. The world of the game is based on the ancient Finland in the late Iron Age.
Stendhal is a full fledged multiplayer online adventures game (MMORPG) developed using the Arianne game development system.
Stendhal is totally platform independent(windows Macintosh, Linux), written using Java 1.5 and the Java2D environment. You can also get the source code, and add your own ideas to the game!
