[nl]

There's TREC QA, which finished in 2007[1]. This year they are doing TREC Live QA[2] (which looks pretty challenging!)

Outside TREC, there is the CLEF QA track[3]

[1] http://trec.nist.gov/data/qamain.html

[2] https://sites.google.com/site/trecliveqa2015/

[3] http://nlp.uned.es/clef-qa/