Steve Martin is famous for wild-and-crazy antics. But in his debut as a Broadway author and composer, he drops the arrow-through-the-head zaniness. He and co-writer Edie Brickell aim straight for the heart in a new musical about love, loss, family and forgiveness. Called 'Bright Star,' the show isn't a bullseye. But it's sweet and tender and boasts a fine cast...Martin and Brickell's bluegrassy score is mellow and pretty. But it's also repetitive -- melodically and lyrically...Director Walter Bobbie ('Chicago') and choreographer Josh Rhodes keep the show chugging along...Cusack, a Broadway rookie, consistently shines -- even when 'Bright Star' doesn't.