One of Milwaukee’s prettiest indie-pop bands calls it a night this weekend, when Sleep Tight Co. play one final show following singer-songwriter Aaron Spransy’s recent move to Boston. As if the night weren’t bittersweet enough, the show will also serve as the release party for the group’s first and last album, We Need a Little Symphony, a collection of violin-kissed tunes that recall Elliott Smith on one of his happier days, and concludes with a rousing version of Prince’s “Raspberry Beret.” The album is available for free download at Canarycoalmine.com/STC.