Butler's only all Mopar car show, Mopars in the Park, sponsored by Butler Pentastars Car Club, is set for 10 a.m. to 5 p.m. Aug. 31 at Alameda Park, off New Castle Road.

Car registration will be from 9 to 11:30 a.m. for $14 per car. Free T-shirts will be given to the first 100 registered.

Trophies will be awarded. Music is planned and food will be available.

For more information, call Scott Snow at 724-285-9484.

FRANKLIN — The Pennsylvania state stone skipping championship will be held Aug. 23 at River Front Park.Among the participants will be the current Guinness Book of World Records holder Russ Byars, previous world record holder Kurt Steiner, and some national competitors from Mackinac Island, Mich.Entry into the competition is open to anyone, and spectators can watch from the banks of the Allegheny River for free.Other activities at the Rock in River Festival include a youth and amateur division stone skipping contest, rock painting contest, kayaking and barbecue.The professional stone skipping championship will be held at 3 p.m.Further details can be found at www.pastoneskipping.com and at www.prostoneskipping.com.For more information, call Russ Byars at 814-671-3304 or send e-mail to rbyars@gmail.com.

PITTSBURGH — The 18th annual Celtic Celebration is set for Sept. 5, 6 and 7 at the Riverplex, 1000 Sandcastle Drive in West Homestead.Celtic music, dance, food and beverages, an Irish dog tent, artisans, historians and vendors will be featured.Hours are 4 p.m. to midnight Sept. 5, 11 a.m. to midnight Sept. 6 and 9 a.m. to 6 p.m. Sept. 7.Tickets for adults are $8 in advance and $10 at the gate or $8 for senior citizens older than 60 and students with ID; $5 for active or retired military with ID, $3 for children ages 3 to 12 and free for children younger than 3.For more information, call 412-422-1113.

PITTSBURGH — The University of Pittsburgh's Allegheny Observatory will have a free open house from 7 to 10 p.m. Oct. 3.Groups of visitors will enter every half-hour. Reservations are required and tickets are available now.During the open house, visitors can wander the observatory and peer into the night sky through the 30-inch Thaw Refractor telescope, usually reserved for research.The observatory is at 159 Riverview Ave.For reservations or more information, call 412-321-2400 between 9 a.m. and 5 p.m.

OIL CITY — The Capt. Erick M. Foster Memorial Fireworks Exhibition is planned for Friday. The program will begin at 5:30 p.m. with music and speakers. The fireworks display will begin at dusk.Seating is available for $20 for stadium seating and $5 for lawn seating. Funds raised will benefit the Wounded Warrior project, a nonprofit organization that works to raise awareness about the needs of severely injured service men and women.More information is available at the Web site, www.aptfostermemorialfireworks.org.

SEWICKLEY — The Sewickley Fall Gallery Walk will be from 5:30 to 9 p.m. Sept. 12.Participating venues include the Sweetwater Center for the Arts, Sewickley Gallery & Frame Shop, International Images, Élan Fine Art Gallery, House of Two Sisters, The Penguin Bookshop, Clearview Federal Credit Union, and Sewickley Herald — Gallery 30.Live music sponsored by Little Athens will be on Locust Street. Free metered parking starts at 4 p.m.For more information, visit the Web site at www.sweetwaterartcenter.org/gallerywalking.asp.