For those folks who have a passion for music and a tendency to root for the underdog, the Guild Theater will offer a unique experience in commemorating a four-stringed instrument that has more than served its time outside of the spotlight: the ukelele. Rock That Uke, a documentary on the mystical allure of the ukulele and its gradual evolution into the mainstream music world, features artists such as Camaig de Forest, Sounds from a Random House, Janet Klein, as well as many others. The film will be shown on both Friday and Sunday night at 7 p.m., with a live performance by Ukulele Loki's Gadabout Orchestra beginning at 8 p.m. following Friday's showing. Academy Award-winner Holly Hunter