Haris has let us know about a Fallout MUD-type game called Ashworld. Here's a little snippet from their FAQ:
What is the AshWorld?
AshWorld is a MMORPG (Massive Multiplayer Online Role Plaing Game). The world of AshWorld is mostly based on the great computer games: Fallout and Fallout 2.
If it is an RPG what can I do?
You can attack other players, wander through the wasteland or assign yourself into quests.
It seems like an interesting game. Give it a go, and tell us what you think.