MUME - Multi Users in Middle Earth
One word describes MUME very closely to reality: AWESOME. I have played MUME for two years now, and since then, I tried to play other MUDs. Most of them are much more confusing than MUME. Of course, when I played MUME, it was hard for me to get all the different types of commands, but then, you don't need that many. There are plenty of nice folk playing out there (though you can meet someone real mean). If you're confused, they'll help you. If you need money, they'll share. For example, if you died, and your level is too high to get a newbie kit, you can ask them so spare some money, and someone usually comes and gives you some. Once I even got 10 gold from a person (a very good amount of money for an average-level player).
And I'm not talking about the cool Tolkien theme. I'm a very big fan of Tolkien, and it's fun to know more than the game to tells you about the place where you are standing.
If you're a hardcore Tolkien fan, that this MUD is for you no doubt. If you're not, well... I think you'll enjoy it anyway.