The Old Stone House will celebrate colonial America on Saturday with demonstrations of routine activities practiced in that time period. The noon to 5 p.m. living history program will include re-enactors, demonstrators and history enthusiasts. Donations of $3 per person or $5 per family are suggested. Managed by Slippery Rock University, the Old Stone House is at the intersection of Routes 8, 173 and 528 in Brady Township. Call 724-738-4964.

Butler County Philatelic Society will sponsor the 67th Butlerpex, a stamp exhibit and exchange, from 10 a.m. to 5 p.m. Friday and Saturday at the Tanglewood Center, 10 Austin Ave., Lyndora. Planned are a post office, show cachet, auction, children's table and 13 vendors. Admission and parking are free. Call 724-443-5740.

Harmony Museum on Mercer Street in Harmony offers guided tours that include the 1809 main museum building and wine cellar and a neighboring early 19th century house, both built by the communal Harmony Society, and a Mennonite log house. Tours are offered 1 to 4 p.m. daily except Mondays. Admission is $7 for adults, $6 for senior citizens, and $3 for youth ages 6 to 17. Call 724-452-7341 or visit www.harmonymuseum.org.

Old Economy Village in Ambridge offers admission for $10 for those ages 12 to 64, $9 for senior citizens, $6 for children ages 3 to 11, and free for active military personnel. Old Economy is open 10 a.m. to 5 p.m. Tuesdays through Saturdays and noon to 5 p.m. Sundays. Call 724-266-4500.

Phipps Conservatory and Botanical Gardens, 1 Schenley Park, presents its May Market bringing together staff horticulturists and members of local garden clubs, nurseries and farms for a plant and garden accessory sale from 9:30 a.m. to 7 p.m. Friday and 9:30 a.m. to 5 p.m. Saturday. May Market admission is free. A butterfly forest continues through Sept. 2, and the summer flower show, Glass Roots, runs through Oct. 6. Conservatory hours are 9:30 a.m. to 5 p.m. daily and until 10 p.m. on Fridays. Conservatory admission is $15 for adults, $14 for senior citizens and students, and $11 for children ages 2 to 18. Call 412-622-6914 or visit phipps.conservatory.org.Heinz History Center, 1212 Smallman St., concludes the exhibit “1968: The Year That Rocked America” on Sunday. Center admission is $15 for adults, $13 for senior citizens, and $6 for students and children ages 6 to 17. Call 412-454-6000 or visit www.heinzhistorycenter.org.Children’s Museum, 10 Children’s Way, Allegheny Square, has reopened the Waterplay area. Hours are 10 a.m. to 5 p.m. daily. Admission is $13 for adults and $12 for senior citizens and children ages 2 to 18. Call 412-322-5058 or visit www.pittsburghkids.org.Carnegie Museum of Natural History, 4400 Forbes Ave., Oakland, has opened Discovery Basecamp. This new, 1,900-square-foot gallery is devoted to hands-on, interactive learning for all ages and features real and replica specimens, educational kits, and tools for observation. More than 60 fine art jewelry pieces inspired by nature are on display in “Garden of Light: Works by Paula Crevoshay” through Aug. 11. Museums hours are 10 a.m. to 5 p.m. Tuesdays to Saturdays, with extended hours until 8 p.m. Thursdays, and noon to 5 p.m. Sundays. Admission is $17.95 for adults, $14.95 for senior citizens, and $11.95 for students with ID and children ages 3 to 18. Admission after 4 p.m. on Thursdays is $10 per adult/senior citizen and $5 per student/child. Call 412-622-3131 or by visiting www.carnegiemnh.org.