Seems like yesterday was the RDF day at Freshmeat.net with 4 RDF-related posts on one day!
The first one I recogniced (Joseki) I've already mentioned below.
Here are the other ones:
* IsaViz is a visual authoring tool for RDF
* Jena is a semantic web toolkit
* sesame is an Open Source RDF Schema-based Repository and Querying facility.
It's really nice to see that the semantic web is going further every day!