Wednesday evening’s script calls for Ava Gardner and popcorn as the Morrill Memorial Library continues its “Broadway Musicals on the Big Screen” summer series with a free screening of “Show Boat” at 6:30 p.m. The 1951 film also stars Kathryn Grayson and Howard Keel. Popcorn will be provided courtesy of the Bellingham Regal Cinemas. Registration is required and can be arranged at the library or by calling 781-769-0200, ext. 222. Wrapping up the series on Aug. 27 will be the 2005 version of “The Producers,” starring Nathan Lane, Matthew Broderick, Uma Thurman, and Will Ferrell. The film festival is being underwritten by the Friends of the Library.