ROCK PAPER SCISSORS formed when Iowans Miranda Mallard, Darla Murphy and Gemma Cohen realized that harmonizing was their collective fate. The trio credits a wide range of influences for their unique selection of cover material, and for the depth and breadth of their original compositions — listeners will detect traces of everything from the Andrew Sisters to the Roches to traditional folk to medieval mass during their performance. The evening will open with a short performance by a local singer/songwriter. Sponsored by the Friends of the Library. 7:30 p.m.