It’s all a little predictable but who cares? If you want an easy, lighthearted time at the movies, with art house overtures and readily identifiable creative class type characters, Leslye Headland’s Sleeping with Other People (opening Friday at the Main Art Theatre) can fill the bill. You’ve seen this kind of plot before - many times. Long-time platonic friends (Alison Brie as Lainey and Jason Sudeikis as Jake) are really sexually attracted to one another but for one reason or another can’t act on it. He’s a womanizer extraordinaire. She’s still in love with her ex (Adam Scott as Matt), the dorkiest guy this side of The Big Bang Theory. Jake’s witty and Lainey is bright and articulate. He sleeps around and that’s understating it. She hasn’t has an orgasm in a year. They talk incessantly about relationships and, yes, sex. In one of the most titillating scenes in a film in some time Jake teaches Lainey how to masturbate, using a juice bottle. One of the best things about the film is the dialogue (also written by Headland). If the plot’s been done before at least you can be entertained by Jake’s incessant one liners. He tells Laney she’s “addicted to mediocrity” and that Matt has “the charm of a broken Etch A Sketch,” and that an inadvertent one night stand between them back in college was “purely driven by social insecurity.” But despite a hands off policy they tend to do couple-like things, including him accompanying her to a lingerie shop, and showing up for a co-worker’s kids’ birthday party, where Laney ends up meeting Chris (Marc Blucas) and they get it on. The movie is a series of false romantic turns. At one point Jake seduces his boss Paula (Amanda Peet) in a relationship that doesn’t go anywhere. Laney finally decides to leave New York for medical school in Ann Arbor, with Jake telling her good naturedly to get out of town as she climbs into the U-Haul. But this isn’t the end of the story. Jake, arrested after attacking Laney’s old flame Matt in a restaurant, tells Laney he’d “rather fail with you than win with anyone else.” That seals the deal. They marry, and walk down Fifth Avenue for a one night honeymoon at The Plaza, before flying back to Michigan. It’s a modern they lived happily ever after.