Maridon Museum, 322 N. McKean St., will host a class on mahjong — a Chinese tile game — for beginners from 12:30 to 3:30 p.m. Friday as well as Sept. 12 and 14. The class is free, but reservations are necessary. Call 724-282-0123. The Maridon is open 11 a.m. to 4 p.m. Wednesdays through Saturdays. Admission is $4 for adults, $3 for senior citizens and students, and free for children younger than 8. Tours are available with advance notice.

Saxonburg Area Artists Cooperative, 215 Main St., rear, Saxonburg, is open 1 to 9 p.m. Fridays and 10 a.m. to 8 p.m. Saturdays. Admission is free. Call 412-260-5779, 724-352-1795 or 412-849-4648. The gallery will feature art demonstrations during the Saxonburg Festival of the Arts Sept. 8 and 9.

Red Brick Gallery, 17 Main St., Foxburg, is featuring “Botanicals and Beyond,” a mixed media exhibit, Friday through Oct. 7. A reception will be held from 2 to 5 p.m. Sunday. Gallery hours are 4 to 8 p.m. Fridays, noon to 8 p.m. Saturdays, and 1 to 6 p.m. Sundays. E-mail edmonds@embarqmail.com.Hoyt Institute of Fine Arts, 124 E. Leasure Ave., New Castle, presents the work of three contemporary artists from the mid-Atlantic region through Oct. 5. A reception will be held from 6 to 8 p.m. Friday. Admission is free. Hours are 11 a.m. to 8 p.m. Tuesdays and Thursdays and 11 a.m. to 4 p.m. Wednesdays, Fridays and Saturdays. Call 724-652-2882 or visit www.hoytartcenter.

Carnegie Museum of Art, 4400 Forbes Ave., presents “Natural History,” an exhibition that explores the ways contemporary artists respond to nature, through Oct. 14. Hours are 10 a.m. to 5 p.m. Tuesdays through Saturdays, with additional hours until 8 p.m. Thursdays, and noon to 5 p.m. Sundays. Admission is $17.95 for adults, $14.95 for senior citizens, $11.95 for students with ID and children ages 3 to 18, and free for children younger than 3. Call 412-622-3131 or visit www.cmoa.org.Society for Contemporary Craft, 2100 Smallman St., hosts “Humor in Craft” through Oct. 27. Gallery hours are 10 a.m. to 5 p.m. Mondays through Saturdays. Admission is free. Call 412-261-7003. A glass exhibit, celebrating the 50th anniversary of the development of studio art glass in America, runs through Sept. 30 at the satellite gallery at BNY Mellon Center, 500 Grant St.