Freebase

Freebase is a community-curated database of well-known people, places and things. It is a large collaborative knowledge base consisting of metadata composed mainly by its community members. It is an online collection of structured data harvested from many sources, such as Wikipedia, ChefMoz, the Notable Names Database (NNDB), the Fashion Model Directory (FMD) and MusicBrainz.

see: http://www.freebase.com/ & http://en.wikipedia.org/wiki/Freebase