San Francisco 49ers' star tight end Vernon Davis is keeping busy early in the offseason.Davis is in Sochi, Russia for the Winter Olympics, pursuing his passion for the sport of curling, which he picked up early in his NFL career. Davis is the unofficial team captain for the United States team. Davis explained his love of the obscure sport in a feature on"They're always like, 'Vernon, what are you doing? What are you doing with curling?