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.
Phaos is a browser-based MMORPG. It features character creation, the ability to purchase/sell/drop potions, weapons and armor, traveling, inter-player chat, the ability to fight in the arena, explorable dungeons, an admin system, the ability to trade with other players, and the ability to fight other players. A download is available for people running Windows who do not have access to or do not want to set up a Web server.
The Second Life Viewer is the client for logging into the Second Life 3-D virtual world, where residents explore, purchase virtual land, open businesses, build real estate, and create scripted objects such as cars, robots, or magic wands. Second Life residents retain full intellectual property rights for the digital content they create and upload, including avatar characters, clothing, scripts, textures, objects, and designs.
TinyMUX is a text-based game server in the MUSH family. It is a platform that allows several thousand players to connect to a single text-driven environment, and interact with each other and with the environment (which is maintained in a database). The rich programming environment can be used to build almost anything, limited only by the developer's imagination.