Another RDF server and Query Engine

Sesame is a scalable, modular, architecture for persistent storage and querying of RDF and RDF Schema, using an RDF Schema Query Language (RQL).

It also seems to support security as well as ontologies.

And what's that it available on Sourceforge:
http://sourceforge.net/projects/sesame/

The online demo is here:
http://sesame.aidministrator.nl/sesame/index.jsp