Free MMORPG Engine. Develop and host graphical browser-based games.
DimensioneX is a free Massive Multiplayer Game Engine.
It lets you develop and then run or host browser-based, graphical multiplayer games. The users will play games simply via their browser.
DimensioneX runs on any Java-enabled web server (eg. Tomcat)
Alfaws is a customizable, multi-user game engine. Every object, character, & room is programmed to respond to events. Players can customize their own event handlers, thus changing their fighting style or having their character behave as they would.