— The 12th annual Penn-Mar Irish Festival promises live music, dancing, poetry, film, children’s activities, food, arts and crafts and more from 10:30 a.m. to 7 p.m. Saturday. Bring lawn chairs, but leave pets and coolers at home. Admission: $7 in advance or $10 at the gate for adults, free for children 12 and under. Information: (888) 273-4507 or penn-mar.org.

— The York City 3-on-3 Roundball Tournament heads indoors this year, with air-conditioned basketball matchups from 8 a.m. to 6 p.m. Saturday in the Voni Grimes and William Penn Senior High School gyms on College Avenue. Spectator admission is free. Information: 849-2245 or www.yorkcity.org.

— The York Post Card Club’s 22nd annual Post Card Show runs from 8:30 a.m. to 4 p.m. Saturday at the Holiday Inn and Conference Center, 2000 Loucks Road, West Manchester Township. Several dealers from around the region will have millions of collectibles for sale, and attendees will be able to vote on themed exhibits created by local club members. Admission: $2 (free after 2 p.m.).

— The excitement of the York Aviation Days returns from 9 a.m. to 7 p.m. Saturday and 9 a.m. to 5 p.m. Sunday at the York Airport along Route 30, west of York near Thomasville. Admission is free, and the show features antique aircraft and cars to explore, a variety of displays, refreshments and more. Proceeds benefit the Faith Flyers. To arrange a ride in a T-6 Texan warbird, call (703) 554-4594. Information: yorkflighttraining.com.

— The annual Father’s Day Fly-In of the Mason Dixon Sport Flyers Club features a full day of fun Saturday for the public, including displays of airplanes and cars, flight demonstrations and plane rides, sports, food, movies and more at Footlight Ranch, 380 Kralltown Road near Wellsville. Admission is free. Information: 432-4441, www.mdsfclub20.com or www.footlightranch.com.

— The Father’s Day Nature Ramble, designed for dads by themselves or families honoring dads on their special day, goes from 2:30 to 4 p.m. Sunday at Nixon County Park, 5922 Nixon Drive, Springfield Township. The free hike will explore the park’s woods and streams. Information: 428-1961 or www.yorkcountyparks.org.

— The Latshaw “Sounds of Hollywood” production delivers a 90-minute lunchtime showcase of silver screen hits with an orchestra, singing and dancing Monday at the Wisehaven Banquet Center, 2985 East Prospect Road, Windsor Township. Lunch starts at 11:30 a.m., with the show at 1 p.m. Tickets: $48.95. Information: 1-800-528-7429 or www.latshawproductions.com.

— Join the Cupcake War at the Paul Smith Library of Southern York County, 80 Constitution Ave., Shrewsbury, by signing up before 5 p.m. Tuesday and competing for public acclaim. At 7 p.m., chef Susan Notter of New Freedom will demonstrate how to sculpt with sugar. Cupcake War winners will be named after the demonstration. Information: 235-4313 or www.yorklibraries.org.

— Marc the Magic Man will perform at 1 p.m. Saturday at the First Presbyterian Church of York, 225 E. Market St., to support the church’s mission to India. The show also will feature music and mission talk. Tickets: $15 for adults, $10 for ages 4-16. Information: 843-8041 or fpcyork.org.

— Spend the morning hiking around Lake Williams with naturalist Kelsey Frey on Saturday and learn to identify plant species, observe wildlife and study the lake’s history. The program starts at 9 a.m. at the Nixon County Park Nature Center, 5922 Nixon Drive, Springfield Township, and features a 5-mile hike for ages 10 and up that lasts until 12:30 p.m. Participants are encouraged to dress for the weather and bring a snack, water and binoculars to enjoy the free hike. Registration is required. Information: 428-1961 or www.yorkcountyparks.org.