You have to hand it to a movie that features a top-notch acting job from Tom Arnold. Happy Endings has that and hottie Maggie Gyllenhaal, as a singer who is having sex with Arnold and his gay son (Jason Ritter). There's also the ever-deft Lisa Kudrow, who is trying to find the son she gave up for adoption. And there's Steve Coogan, who broods that his lover (David Sutcliffe) provided the sperm that brought a baby to their lesbian best friends (Laura Dern and Sarah Clarke). Writer-director Don Roos knows how to mix angst and comic ardor, as he did splendidly in The Opposite of Sex. Here his touch isn't so sure. The film rambles, but rambling with the mischievous Roos is still a tricky and winning proposition.