Associated Artists of Butler County is offering professional art classes by watercolor artists Bill Perry and Peggi Habets. Call 724-282-6922 for information. The Art Center, 344 S. Main St., also hosts art parties for groups. Gallery hours are noon to 6 p.m. Wednesdays through Fridays and noon to 4 p.m. Saturdays. Admission to the center is free.

Maridon Museum, 322 N. McKean St., 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. Guided tours are available with advanced notice for no extra charge. Call 724-282-0123 or visit www.maridon.org.

Carnegie Museum of Art, 4400 Forbes Ave., is displaying “Inventing the Modern World: Decorative Arts at the World's Fairs, 1851–1939” in the Heinz Galleries through Feb. 24. Work by New York City-based contemporary artist Cory Arcangel continues through Jan. 27. Museum 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 and children ages 3 to 18, and free for children younger than 3. Call 412-622-3131 or visit www.cmoa.org.