SPARQL is an RDF query language and protocol produced by the W3C RDF Data Access Working Group (DAWG). It was released as a W3C Recommendation in January of 2008.
See also
SparqlImplementations -- A list of implementations
SparqlProtocolDiscussion -- how to quick-hack before the protocol spec is finished
SparqlBenchmarks -- a list of benchmarks for the SPARQL query language
DawgShows -- A list of live demos on the web
SparqlEndpoints -- URLs with SPARQL exposed over HTTP binding
SparqlEndpointDescription -- how to describe capabilities and content of SPARQL endpoints
SPARQL Extensions -- a catalog of existing and potential extensions of the SPARQL language and protocol
SparqlExtensionFunctions -- List of SPARQL extension (filter) functions
SparqlUpdateLanguage -- Extending SPARQL with functions for updating RDF datasets