The MUGU Project is creating an multiplayer graphical game system for customizable worlds. It encourages role playing and includes both a client and server.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.
This release includes much refactoring of the code, internationalization support, an overhaul of the client, and some miscellaneous minor feature enhancements.