A Tempest Season
The best MUD I've played in a long, long while, possibly ever. It is definitely the most player-friendly! RP is enforced and rewarded, which is very nice, and the staff is the nicest and most helpful I've ever met. The system itself is also great -- well-crafted areas that are always growing, non-automated combat, and tons of quests to do. I just can't say enough good things about this game, really. Well worth playing, and so much more!