Giant Recalls Anthem X 29er Bicycles Due to Fall Hazard.  This recall involves 2011 model year Giant Anthem X 29er 1, 2 and 3 model bicycles. The bicycles were sold in small, medium and large. “Giant” and the model name are printed on the bicycle.  The frame can crack at the junction of the seat post and top tube, posing a fall hazard to riders.

http://www.cpsc.gov/cpscpub/prerel/prhtml11/11038.html