This week, everybody is talking about an ultra-gory killer-clown movie (Terrifier 3) beating out a tamer killer-clown movie (Joker: Folie à Deux) at the box office. Meanwhile, Saturday Night, a behind-the-scenes chronicle of the birth of "Saturday Night Live," premiered in seventh place, despite the comedy bona fides of director Jason Reitman (Up in the Air, Juno, Ghostbusters: Afterlife). Perhaps this period piece has limited interest for the younger folks, while the older ones are waiting for streaming or don't want to taint their memories of beloved comedians by watching actors imitate them. What are they missing? The deal It's October 11, 1975, approximately 90 minutes before the premiere of a live sketch-comedy show called "Saturday Night" on NBC. In the Manhattan studio, chaos reigns. Fresh-faced network suit Dick Ebersol (Cooper Hoffman) is rooting for the show that he hired young Canadian comedy writer Lorne Michaels (Gabriel LaBelle) to create. Michaels tells executive Dave Tebet (Willem Dafoe), who represents the NBC old guard, that he envisions "Saturday Night" as the only show "by and for" the first generation to grow up watching television: a showcase for boomers, with a brand-new comedy sensibility to match. Tebet is amused but not convinced. To him, "Saturday Night" is merely a pawn in a contract dispute with all-powerful late-night host Johnny Carson (Jeff Witzke), who offers Michaels a poisonous welcome by phone. Tebet has the power to ax the new show before it airs, and he might do just that. Meanwhile, Michaels can't decide which sketches will make the air; his potential breakout star, John Belushi (Matt Wood), keeps going on the lam; audio and lighting mishaps abound; the set isn't finished; the host, George Carlin (Matthew Rhys), is openly contemptuous of the show; the censor (Catherine Curtin) wants to chop up the script; players Garrett Morris (Lamorne Morris) and Jane Curtin (Kim Matula) wonder what they're even doing there; comedy legend Milton Berle (J.K. Simmons) wanders around causing trouble; and no one treats Jim Henson's (Nicholas Braun) Muppets with the proper respect. Will you like it? I'm not of the generation that "Saturday Night Live" was made by and for, according to the movie. But as a child of the 1970s, one of my great ambitions was to stay awake all the way through an episode. Before the players were household names and the show became an institution, those 90 minutes…