Friends with Benefits

“Friends With Benefits,” a breezy, speedy and (no kidding) funny comedy with a nicely matched Justin Timberlake and Mila Kunis that is about love and sex in the age of social networking, gets some of its juice and tang partly by trash-talking its own genre. The setup is familiar, as are the essential elements: a single man and a single woman, two battered hearts yet a pair of resilient, eager, pretty bodies. But Ms. Kunis’s character is dark and savvy, not blond and dippy, and when she comically rails against an unseen Katherine Heigl you may sigh with relief (fingers crossed) that you’re watching the “Scream” of romantic comedies.