Apotheosis TRPG
A Java-based tactical RPG created for a high school project.
...It makes use of an XML database which can be modified by users to create new content such as maps, units, weapons, items, and armor. The XML parsing and serializing methods employed by the game engine make use of both the XOM (http://www.xom.nu/) and XStream (http://xstream.codehaus.org/index.html) open source Java XML libraries.