MEDIEVAL FESTIVAL in Fort Tryon Park (Sept. 29, 11:30 a.m.-6 p.m.). An era known for disease, drudgery and dubious hygiene, the Middle Ages weren’t exactly glamorous. You might never guess that, though, if your impressions come from this free annual festival in Upper Manhattan, which emphasizes period chivalry and general good cheer. Presented by the Washington Heights and Inwood Development Corporation, the fair turns the area around the castlelike Met Cloisters into a medieval-style village. This festival, the 35th, will go on rain or shine and entertain young visitors with sword fighting (and sword swallowing), acrobats and aerialists, a friendly dragon, falconry demonstrations, storytelling, an interactive Robin Hood performance and jousts in which armored performers really do knock one another off horseback. Children who would like to get in on the act can dress up for a 4 p.m. parade (the information booth will have complimentary costumes, first come first served) and try swordplay with plastic-foam weapons. Girls are welcome to practice being knights as well — one way that the festival isn’t quite so medieval.

212-795-1600, whidc.org

[Read about the events that our other critics have chosen for the week ahead.]

‘THE SECRET WORLD OF ARRIETTY’ at select movie theaters nationwide (Sept. 29, 12:55 p.m.; Sept. 30, 7 p.m.). The 14-year-old heroine of this animated film from the renowned Japanese company Studio Ghibli lives in a world where postage stamps are wall art, a staircase is made of nails, and a house cat is a giant monster. As fans of Mary Norton’s books will recognize, that’s because Arrietty is a Borrower, one of a clan of tiny people who live in the nooks and crannies of old houses and furnish their abodes with the small possessions of ordinary humans. Fathom Events and the distributor GKids are presenting the feature, an adaptation of the first Borrowers book, in an English-dubbed version (with the voices of Amy Poehler and Carol Burnett, among others) on Sunday and in Japanese with English subtitles on Monday. Part of Studio Ghibli Fest 2019, the adventure, which was directed by Hiromasa Yonebayashi, chronicles the budding friendship between Arrietty and Shawn, the normal-size boy who discovers her. “Studio Ghibli and Arrietty have a way of taking you where you may not expect,” Manohla Dargis wrote in The New York Times in 2012.

fathomevents.com

‘THE STRAY’ at the Theater at the 14th Street Y (Sept. 28, 11 a.m. and 1 p.m.; Sept. 29, 1 p.m.; through Oct. 6). As its name implies, the educational theater company Rebel Playhouse does not encourage following the crowd. Or, in this show, the pack. A folk musical written and composed by Arif Silverman, “The Stray” features three wolf cubs whose behavior could hardly be more radical for their species: They’re vegetarian. When this causes them to be expelled by their fellows, they challenge norms again by trying to bond with humans. Presented with the Theater at the 14th Street Y and intended for audiences ages 5 to 9, the hourlong production illustrates that nonconformity has its own rewards.

646-395-4310, 14streety.org

SUBMERGE MARINE SCIENCE FESTIVAL at Pier 84, Hudson River Park (Sept. 28, 11 a.m.-4 p.m.). An estuary is where freshwater converges with seawater, but that won’t be the only meeting that these free festivities will celebrate. Children can look forward to working alongside scientists and anglers, as well as encountering birds of prey and aquatic animals like eels, terrapins, horseshoe crabs and oyster toadfish. Taking place at Pier 84, at the western end of 44th Street (registration is recommended, and the rain date is Sunday), the event will offer an area where young visitors can examine plankton under a microscope, observe an oyster dissection and design their own filtering devices with researchers from Hudson River Park’s Estuary Lab. They can also enjoy kayaking, catch-and-release fishing and marine-themed demonstrations and entertainment presented on the festival’s Science Stage.

hudsonriverpark.org