(Cleveland) -- Northeast Ohio's annual spring break mainstay opens today with new rules to keep the event family-friendly. I-X Indoor Amusement Park organizers say visitors under age 18 must be with a chaperone after 5 p.m. The rule was drafted after a "flash mob" of teenagers started fights last year in the I-X Center. More details on the policy and tickets are online at ixamusementpark.com.