Summer movie season is ending, so now its time for films about the Kennedy assassination. Parkland tells the story of the people around the situation — the Secret Service agents, doctors, nurses, and random guys with cameras. Produced by Tom Hanks, it stars Paul Giamatti, Marcia Gay Harden, Billy Bob Thornton, Zac Efron, Mark Duplass, Jacki Weaver, Rory Cochrane, Ron Livingston, and Colin Hanks, and opens on September 20.