"OntoBuilder started as a tool (with a user interface) developed in Java. Later, one of the requirements was to implement OntoBuilder as an agent, removing any user interaction required. Therefore, OntoBuilder was implemented as a TCP agent. OntoBuilder can be accessed as a graphical tool, as a command line tool, as an applet, as a java WebStart application, as a TCP server, and using an HTML interface."
Includes ontologies in domains including: car rental, job finding, news, and others. Shouldn't forget about Metalog either.
Also, a new book called Ontological Engineering has just been published (well November 1) just in time for Christmas, the perfect stocking filler.