If you like semantics or if you work on NLP projects, you should already know DBPedia. Database plus a set of tools that allow you to ask sophisticated queries against Wikipedia. Some days ago, DBPedia 3.2 was released and now, it includes DBpedia Ontology, a manually created cross-domain ontology based on the most commonly used infoboxes within Wikipedia.

Read more on the official announcement

Note: I'm a bit late on this news, I will try to update the blog more often.