Time to break out the Doc Martens and hair beads again. The two staples of ’90s rock radio — see: “Amber” and “Down” for Omaha’s reggae-fied groovers 311, and “Come Out and Play (Keep ’Em Separated)” and “Self Esteem” for L.A. pseudo-punks the Offspring — are doing a summer tour together, and they’re bringing ’00s one-hitters Gym Class Heroes as the opening band. (7:30 p.m. Aug. 31, grandstand, $49 and $59, etix.com.)

Chris Riemenschneider