WorldForge is the original open-source MMORPG project, dating back to 1997 (Linux and Windows Supported!)
http://www.worldforge.org/About Worldforge
The Worldforge project aims to provide tools to allow for anyone to build their own virtual worlds, and others to experience these worlds.
We do this by providing a complete set of software, with everything from servers to clients to protocols and tools. And everything we do is 100% Free Software. That means that you can see all of the code, and make changes to it. In fact, we encourage you to make changes. Impress us!
The project has a long history. We've been doing this for a while, and we're in it for the long haul. We do think we're on to something great, and we want to share that with you. That's why we're encourages you to try out our worlds already today. They might be rough around the edges, and there might be work still to do, but we're hoping that you'll see the potential.
If you think that this sounds interesting and want to help us out we would be delighted. We've even made a whole section of our site into a guide for would be developers. Perhaps you want to help out with coders. Or you're a great artist. Or you have any other skill that might be useful. If so, head over to the Develop section.
Introduction to WorldForge
Our vision is to foster an independent community, active in the development and maintainance of many unique roleplaying-oriented game worlds, with access to a rich collection of game rules and audio/visual media, a wide selection of server and client implementations, and a standard network communication protocol.
WorldForge's mission is to produce the necessary tools and technologies that will allow the creation of graphically rich games of cooperation and socialization. We strive to blur the distinction between player and maker, and wish to establish a positive community environment for current and future free game developers.
Worlds
While the whole Worldforge project is designed to allow for you to create your own world we do provide some default worlds. These are mainly meant to be used as examples of what you can do, and as starting points for your own creations. The Worlds are defined using XML declarations, and are meant to be loaded into a running instance of Cyphesis, using the cyimport command, like such:
Deeds
The default ruleset is called "Deeds". The ruleset defines the rules of the world, i.e. how things behave. By altering the ruleset you change the rules of the world. The Deeds worlds are all set in a fictional fantasy world called Dural. It's your basic medieval RPG setting.
The focus of Deeds is on simple combat and crafting mechanics.
The island of Braga
Our default world is the island of Braga, a rather small island in unknown waters. The world is designed to teach the user the basic gameplay mechanics and to introduce some simple combat and crafting situations.
http://www.worldforge.org/