FREE. Boys & Girls Club of Missoula County and River City Roots are pleased to offer a concert for the whole family! Local band Letter B will be rocking the Caras Park Stage as part of the River City Root Festival! Starting at 6pm, this is a FREE concert for the family to enjoy. Food vendors and a small bar will be available at Caras Park. You can even buy your Roots Fest cup and wristband at the venue.