Selador is a browser-based fantasy game. The game was commercial at first, but has since been released as open source by its developers. The game focuses on teamplay and communication between players. Although it is played in real-time, strategy and planning are paramount. It comes with a nice set of graphics and a pre-populated database. It can be installed on any *AMP stack.
This project has (according to the web site) been discontinued since December 15th, 2007.