It’s an exciting weekend in Warren County as two events, Bluegrass Underground and Taste of the Underground, kick off three days of music on Friday. Drawing people into town from across the United States will be the PBS filming of Bluegrass Underground at Cumberland Caverns that begins Friday at 6 p.m. with The Mavericks, The Chris Robinson Brotherhood, Russell Moore & IIIrd Tyme Out, and Conor Oberst.Individuals looking to purchase tickets for Bluegrass Underground will be sadly disappointed as it is a sold-out show. The same goes for Saturday and Sunday concerts.Tickets are still available for the collaboration with Bluegrass Underground, which is Taste of the Underground offered at Park Theater.