A Twisted+Django server and code base for creating online multiplayer text games (MUD, MUX, MUSH, etc)
Evennia is a game server, library and toolbox for creating multiplayer online text games (aka MUD/MUX/MUSH and other MU*).
Evennia offers great flexibility since you customize and extend the system by having Evennia load your own custom Python modules. This offers game developers the chance to build their own dream game while not having to worry about gritty details such as database management and connection protocols. The API is well-documented and there is an extensive documentation with many tutorials. From the Evennia homepage one can also find an active mailing list and chat room to get help.
Evennia itself does not impose any hard-coded systems on you, so you are free to yourself create combat systems, races or what have you (we have a growing library of contributions to use as starting points though).