The Rex Foundation is the charitable foundation created by the Grateful Dead to support grassroots organizations doing good work in the fields of health, the arts, education and community. The Rex Foundation created the Rex Musical Caravan where bands get on board to support Rex donating a portion of the proceeds to the Rex Foundation. Rex board member, Tim Duncan, whose family owns and operates Silver Oak Cellars in Napa Valley, hosted a Rex Musical Caravan featuring Taj Mahal. Rex board member Bob Weir performed, unannounced, with friends Jay Lane and Rob Wasserman. Here is a short video of one of the the tunes they performed.