Former NBA MVP Dirk Nowitzki is enjoying his offseason. The Dallas Mavericks are still reigning league champions for a little while longer and Dirk was a champion on stage with Folk Rock group the Avett Brothers, at a show in Grand Prairie, Texas. Watch below h/t Hypervocal … [Read more...] about Dirk Nowitzki playing Tambourine on stage at Avett Brothers show (video)