When sex happens once a year

B oasting 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…