At the weekend, I gave a lightning talk at OpenHackLondon about SPARQL. Here are the bits I want to make public. Enjoy. 
First, a memetic bit: "SPARQL is to SQL as dynamic typing is to static. SQL was designed back in the age of the Dukes of Hazzard, not the age of Facebook."
I demonstrated the use of SPARQL with dbpedia (endpoint), LIBRIS (endpoint) and Mulgara.
The queries I ran are up on Gist: dbpedia programming languages with English titles, dbpedia streets in London query, dbpedia query for listing populated cities, a rather goofy dbpedia beauty pageant winner query, LIBRIS query for getting books by author, a query for my Mulgara store of BBC data to get back a list of people on TV and a Mulgara TQL query for doing the equivalent of SELECT COUNT(*).
Yves Raimond, @moustaki, pointed out that the BBC data is now queryable through this endpoint.
Just some links I wanted to point to: SPARQL 2 Feature request wiki page, SPARUL.
