Evennia is an open-source Python-based MUD/MU* server/codebase using modern technologies. Evennia allows creators to design and flesh out text-based massively-multiplayer online games with great freedom.
http://www.evennia.com is the main hub tracking all things Evennia. The documentation wiki is found here.
Evennia aims to supply a bare-bones MU* codebase that allows vast flexibility for game designers while taking care of all the gritty networking and database-handling behind the scenes. Evennia offers an easy API for handling persistent objects, time-dependent scripting and all the other low-level features needed to create a MU*. The idea is to allow the mud-coder to concentrate solely on designing the parts and systems of the mud that makes it uniquely fit their ideas.
Coding in Evennia is primarily done by normal Python modules, making the codebase extremely flexible. The code is heavily documented and you use Python classes to represent your objects, scripts and players. The database layer is abstracted away.
Evennia offers extensive connectivity options. A single server instance may offer connections over Telnet, SSH, SSL and HTTP. The latter is possible since Evennia is also its own web server: A default website as well as a browser-based comet-style mud client comes as part of the package (screenshot). Due to our Django and Twisted foundations, web integration is a snap since the same code that powers the game may also be used to run its web presence (you may use a third-party webserver too if you prefer though). Evennia in-game channels can also be interlinked with external IRC and IMC2 channels so players can chat with people "outside" the game.
Whereas Evennia is intended to be customized to almost any level you like, we do offer some defaults you can build from. The code base comes with basic classes for objects, exits, rooms and characters. There is also a default command set for handling administration, building, chat channels, poses and so on. This is enough to run a 'Talker' or some other social-style game out of the box. Stock Evennia is however deliberately void of any game-world-specific systems. So you won't find any AI codes, mobs, skill systems, races or combat stats in the default distribution (we might expand our contributions folder with optional plugins in the future though).
If this piqued your interest, there is also a lengthier introduction to Evennia to read.
The codebase is currently in Beta. While development continues, Evennia is already stable enough to be suitable for prototyping and development of your own games.
To learn how to get your hands on the code base, the Getting started page is the way to go. Otherwise you could browse the Documentation wiki or why not come join the Evennia Community. Welcome!