The Waltham Arts Council is sponsoring another season of free concerts on the Waltham Common this summer. The nonprofit group’s lineup of 7 p.m. performances continues with the Waltham American Legion Band on Tuesday; the Tom Bruhl Trio on July 31; the Reynolds Band on Aug. 7; Mystique on Aug. 14; the mayor's fifth annual doo-wop concert on Aug. 18; the John Penny Band on Aug. 21; and wraps up with the Reminisants on Aug. 28. Call 781-893-2787  for information on weather cancellations. Bring your own chairs and blankets; refreshments will be available for sale.