DominionsMOO - Small MOO for friendly people and coders.
All players are programmers by default and additional quota is available for building projects.
Hellyeah Moo - A place for hipsters to talk, react, interact and kill time. The MOO that started it all, still available and with a wide playerbase. RiverMOO - Provides opportunities to socialize, participate in gaming, and build creatively. Rupert - Themed around Douglas Adams' Hitchhiker's Guide series.