The annual Summer Steam Show will be today through Sunday at the Portersville Steam Show Grounds, Route 19. The feature at the show will be Massey Harris and related equipment. The show also will include steam demonstrations, children's tractor pulls, a flea market, crafts and square dancing exhibitions. Homemade apple butter, cider and molasses will be available for sale. Visit the Web site, www.portersvillesteamshow.homestead.com.

McConnells Mill State Park, Slippery Rock Township, just over the Butler County line into Lawrence County, will host "The Big Trees" at 2 p.m. Saturday. Wear sturdy shoes and take water. "Art in Nature" is planned for 3 p.m. Sunday. Meet at the Kildoo Picnic Area to design and create your own work. The Old Mill has tours of the grist mill at 1 and 2 p.m. Fridays, 1 and 3 p.m. Saturdays, and 2 and 4 p.m. Sundays. A new turbine has been installed in the mill, and corn grinding will be demonstrated from 11 a.m. to 3:30 p.m. Fridays and 11 a.m. to 5:30 p.m. Saturdays, from Memorial Day through Labor Day. Admission and parking are free. Call 724-368-9320.

Jennings Environmental Education Center, Route 528 near the intersection of Routes 8 and 173, will host a 90-minute walk to discuss the prairie blooms at 2 p.m. Sunday. "Wildflowers of Summer" will take place at 2 p.m. Aug. 17. Healthy Hikes are planned from 6 to 7:30 p.m. Aug. 6, Sept. 3 and Oct. 1. Jennings is open from 8 a.m. to 4 p.m. weekdays and on weekends as scheduled. The trails are open daily from sunrise to sunset. Call 724-794-6011 to confirm programs.

Moraine State Park, along with hosting the Regatta at Lake Arthur this weekend, will be the site of Historic Oil Well demonstrations from 10 a.m. to 4 p.m. Saturday and Sunday. Call 724-368-8811.