AYUMiS is a project aiming to create a cross-platform MMORPG set in space. It is developed in C++ with ClanLib. It will give the player full control over the game universe, with no NPCs or pre-planned storyline. It attempts to give the player a full range of choices and open-ended gameplay.
Arx Libertatis is a cross-platform, open source port of Arx Fatalis, a 2002 first-person role-playing game developed by Arkane Studios. Arx Fatalis features crafting, melee and ranged combat, and a unique casting system where the player draws runes in real time to effect the desired spell. The Arx Libertatis source code is based on the publicly released Arx Fatalis sources. This does however not include the game data, so you need to obtain a copy of the original Arx Fatalis or its demo.
Battletech MUX is an Internet based, real-time rendition of the popular Battletech board game. Players take to the front lines in their very own mechs, tanks, and similar implements of destruction. Featuring an internal scripting language called SoftCode, game admins may sculpt their sites into whatever they can imagine, be it small-scale combat or massive, galactic conflict.
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.