Materia Magica is hands down the best free MUD on the net today. An enormous world, a generally friendly population and a well thought out class and combat system all contribute to the experience. While MM had its problems, as all games do, it still remains head and shoulders above every other free MUD out there (and probably most paid ones too, althought I wouldn't know). It's difficult to say enough about the positives to this game. I first decided to give MM a try when I logged on and was immensely pleased by the color scheme (don't you hate those MUDs that torture your eyes with neon or overly dark text?), and I've been there ever since. Give it a shot.