Tuesday's MEDICINE BALL CARAVAN (11am-noon Central Standard on KRVS 88.7FM locally or www.krvs.org) spotlights new & recent releases by Steve Martin & Edie Brickell, Tim O'Brien, Los Lobos, Lizz Wright and Dayna Kurtz. Also: we'll begin focusing on this weekend's Blackpot Festival with music by Mollie O'Brien, Blayze & Saddles and Michaela Anne. Plus: sounds of Patty Griffin, Grateful Dead, Valerie June, New Riders of the Purple Sage and Dr. John.