And a new option for people in Portland, Maine, is about to debut. Mayhem Portland is Planning a Grand Opening in OctoberAccording to MaineBiz, Mayhem Portland is nearing its grand opening date after months of teasing its arrival. Rage Rooms Have Grown in Popularity in Recent YearsWhen you step inside Mayhem Portland, you'll probably instantly see the appeal. Mayhem Portland plans to offer 30-minute sessions for both their rage and paint splatter rooms. Mayhem Portland has not set an official grand opening date but it is expected in October.