Another R-rated romantic/sex-comedy. Will I ever get tired of watching these? Probably not. It's very formulaic in the macro plot, so all the fun has to come out of the actors' talent, chemistry, and script cleverness. For me, at least, it won on those.
Our couple are Dylan (Justin Timberlake) and Jamie (Mila Kunis); she is a New York-based corporate headhunter, and he is a hunted head: she recruits him away from his popular website, and plunks him down as art director for GQ Magazine. During the process, there's a lot of witty banter and gags. There's an obvious attraction between them, they both make enough money to live beautifully in Manhattan, but they're both coming off bad breakups (he with Emma Stone, she with Andy Samberg), and are relationship-shy. But that's the reason for the title: they decide to go for a sexual relationship without "getting involved" beyond companionship. No strings. Keep it casual. Just fun.
Yeah, that's not gonna work.
Both Justin and Mila do a good job; Justin, in fact, gets extremely funny when he gets to tap into his singing/dancing talents (far beyond what you might expect from a magazine's art director). There's also an extremely talented bunch of supporting actors: Patricia Clarkson as Jamie's mom; Richard Jenkins as Dylan's dad, Jenna Elfman as his sister, and Nolan Gould, one of those kids on Modern Family, as his nephew. And Woody Harrelson as a gay sports guy at GQ. And Shaun White, the ski guy, has a couple of cameo scenes, which are hilarious. And Jason Segal and Rashida Jones appear as a couple in a horribly clichéd romantic comedy movie-in-a-movie. (One possible criticism is that the movie is a bit too meta at times, discussing romantic comedy movie clichés only to commit them a short while later.)