OpenForum is a web application server that can be edited while running, and in the browser. Similar to how a wiki works, OpenForum can be edited by any authorised editor, but rather than just being able to create content, an editor can also create web services.
OpenForum is built around the concept of pages. Each page has a URL eg. /OpenForum/Sandbox. The content for the page is contained in a directory and contains a number of standard files that define its content and its behaviour.