Vendetta Online is a multi-platform 3D space-combat MMO for Windows, Mac, Linux/32 and Linux/64. The game permits players to interact in a vast online galaxy; fighting, trading, and mining their way to success. A "twitch" type real-time combat model makes true player skill the deciding factor instead of character advancement. Massive capital-ship battles shake the foundations of the major nations at war, while others struggle to push back the encroachment of the AI "Hives". A no-strings free trial is available.
Stendhal is a multiplayer online adventure game (MMORPG) developed using the Arianne game development system. It features a rich and expanding world in which you can explore towns, buildings, plains, caves, and dungeons. You will meet NPCs and acquire tasks and quests for valuable experience and cold hard cash. Your character will develop and grow, and with each new level up become stronger and better. With the money you acquire, you can buy new items and improve your armour and weapons. You can also roam the world in search of evil monsters (and kill them).
OpenMW is an attempt to reimplement the popular role playing game Morrowind. It aims to be a fully playable implementation of the game that will run on Linux, Windows, and Mac OS X. No game data is distributed with the code; the user must already own a copy of Morrowind to use the software.
Crossfire is a multi-player graphical arcade and adventure game made for X. It has certain flavours from other games, especially Gauntlet and the rogue-like games (Nethack, Moria, Angband, and Ragnarok). Any number of players can move around in their own window, finding and using items and battling monsters. They can choose to cooperate or compete in the same world.