COUNTYHarmony Museum, 218 Mercer St., presents its final First Friday Museum Shop open house for the summer from 4 to 7 p.m. today, with a celebration of the root beer float, at the Wagner House annex and garden, 222 Mercer St. The museum’s 12th annual antique gun show is 9 a.m. to 3 p.m. Aug. 13 in Stewart Hall at 218 Mercer St. The museum is open from 1 to 4 p.m. daily, except closed Mondays. Call 724-452-7341.

PITTSBURGHCarnegie Science Center, North Side, hosts Olympic Science Weekends on Saturday and Sunday and Aug. 13, 14, 20 and 21. National Parks Adventure Day on Saturday will offer hands-on activities to commemorate the Park Service’s centennial. Center admission is $18.95 for adults and $11.95 for children 3 to 12. Center hours are 10 a.m. to 7 p.m. Saturdays and 10 a.m. to 5 p.m. Sundays through Fridays. Visit CarnegieScienceCenter.org.ToonSeum, a museum of cartoon art, 945 Liberty Ave., hosts the display “Captain America: 75 Years of the Sentinel of Liberty” through Aug. 14. Work by editorial cartoonists is on display through Aug. 28. Admission is $8 for those 13 and older and $4 for those 6 to 12. Military personnel and veterans admitted free. Visit toonseum.org.Children’s Museum, Allegheny Square, hosts “Daniel Tiger’s Neighborhood: A Grr-ific Exhibit” through Jan. 17. Hours are 10 a.m. to 5 p.m. daily. Admission is $16 for adults and $14 for children 2 to 18 and senior citizens. Visit www.pittsburghkids.org.