A comedy full of false notes about being true to yourself. Hawn plays Suzette, a onetime rock groupie who still parties hard. Sarandon is Lavinia, her former ''Banger Sister,'' who married money and raised a picture-perfect family. Soon after seeing Suzette for the first time in 20 years, Lavinia's flinging dinner at her husband, chopping off her hair, and shaking her booty again. But that's how Suzette affects everyone -- including a failed, suicidal screenwriter (Geoffrey Rush) who becomes manically inspired after one round with a Banger. Hawn hasn't seemed such a forced force of nature since 'Butterflies Are Free.'