Down By Riverside presents the first of its Thursday Night Potluck Roots Music Concerts at Arts Collaborative Medford. Featured performer will be Professor Harp, aka Hugh Holmes. The Professor was a rock ‘n’ roll drummer until 1969, when the Boston blues revival and a sterling performance he caught of blues harmonica great George Allen “Harmonica” Smith combined to lure him away from drums to the blues harp. He primarily plays a sparse yet full-sounding brand of no-nonsense, no-frills Texas-style blues. Please bring food to share or for yourself. There will be both alcohol and non-alcohol beverages for purchase. The event is free, but if you can afford it, donations are welcomed to help defray the event’s cost.