In her new film 'Last Weekend,' Patricia Clarkson plays Celia, the manipulative matriarch of a dysfunctional family who decides to have a reunion at the wealthy family's house on Lake Tahoe. But the well-planned weekend doesn't turn out quite as Celia has planned. Chris Mulkey plays her calm, loving husband, and Joseph Cross and Zachary Booth are her spoiled, embittered adult children.