The last chance to ride the 85-year-od Paragon Carousel this season will be Saturday from noon to 3 p.m., at the Spooktacular Halloween Costume Party. In honor of the holiday, the carousel’s Wurlitzer band organ will play Halloween music and the carousel will be appropriately decorated. Participants can enter the parade of costumes at 2 p.m. and compete for best costume prizes in numerous categories. Refreshments will be available, as well as face painting and pumpkins. The carousel will reopen for its 86th season on Nantasket Beach on Easter weekend of 2014. For more information, go to www.paragoncarousel.com or call 781-925-0472.