There are hands-on directors and then there’s Jason Reitman. In town preparing to shoot “Labor Day,” Reitman dropped by the movie’s production office in Natick this week to help Boston Casting’s Angela Peri find extras for the film. We’re told hundreds of actors showed up and Reitman, whose credits include “Juno” and “Up in the Air,” roamed the room with his assistants, saying things like “passengers on a bus” and “five people at the book sale.” At one point, he looked at a woman and said, “I predict you will soon be pregnant,” and joked that he always wanted to say that to someone and then cast her as “pregnant woman.” Based on a book by Joyce Maynard, “Labor Day” will star Kate Winslet and Josh Brolin. . . . Nice to see Sean Slade and Paul Kolderie among the multitudes who made their way to Mansfield to watch Radiohead rock the Comcast Center. Slade and Kolderie, of course, were cofounders of Boston’s legendary Fort Apache Studios and also produced the first Radiohead LP, “Pablo Honey.”