When sex happens once a year

Boasting a blatantly contrived high-concept premise, One Night Only is better than it ought to be. At the same time, the movie — which rides on agreeable performances from Monica Barbaro and Collum Tower — isn’t the winning charmer it might have been. The contrivance: One Night Only, directed by Will Gluck and written by Travis Baum, creates a world in which unmarried people are subject to an oppressive government mandate: They’re allowed to have sex on only one night a year. Don't expect a hard satirical punch; the movie delivers more of a powder-puff pat. The sex mandate stems from a fascistic government that wants to promote marriage and restrain what it regards as profligacy. Gluck surrounds this implausible premise with a spiffed-up version of New York City, where Tower’s Owen operates a pizza restaurant and Barbaro’s Allie sings for a living. Afflicted by stage fright, Allie is relegated to recording songs for commercials, in this case for a drug that’s supposed to help with…