Calling all Chicagoland high school students: Ravinia Festival will host its second annual “Cannonball,” an informal meet-up for all high schoolers at 3 p.m. Sunday, July 29, preceding the 5 p.m. Chicago Symphony Orchestra concert of all-Tchaikovsky masterworks, including the “1812” orchestra with cannons. Admission is free to high school students for both the party and the concert. Just RSVP here so we order enough food! Show your ID at the box office to win double points for your school on July 29 Remember, students win points for their schools with every visit to a CSO concert when they show their IDs, and the school that accumulates the most points by the end of the season will win a $5,000 grant for its music programs from the Ravinia Associates. Pass this information along to any students you know!