A MUD is an online mutliplayer text game where people from all over the world generally connect using a telnet or mud client and go about killing monsters, gaining new items, rising in power and socializing with other players and mud staff. Every mud works a little differently, and some, such as mushes, generally dont have any killing of monsters or mobs in mud terms at all. Instead such things are role played and acted out in text by the players and staff. Muds generally allow you to choose a race, such as human, dwarf or elf, and a class such as warrior, magic user, thief, or priest. You then customize your character more depending on the game you choose to play, and go out into the world, killing monsters which give you experience points. After gaining a certain amount of experience points you raise in level, becoming more powerful, gaining new skills and being able to use better items.

Website: http://www.mudpages.com/