If you're a fan of William Haefeli, whose stale New Yorker cartoons gently tease Manhattan sophisticates, help yourself to this plastic debut comedy by writer-producer-director Sue Kramer. Two exceedingly close siblings (Heather Graham and Tom Cavanagh) despair of ever finding satisfactory love relationships until the brother meets the girl of his dreams (Bridget Moynahan); unfortunately the sister, discovering her homosexuality, falls for the young woman as well. Graham carries this for a while, but Kramer spends entirely too much time weakly satirizing Graham's job at an advertising agency, where Molly Shannon's a kvetching coworker. The dearth of ideas is exemplified at the end by a Mary Tyler Moore freeze-frame of Graham leaping in the air. With Alan Cumming and Sissy Spacek. PG-13, 96 min.