Harmony Museum on Mercer Street in Harmony, offers regular guided tours from 1 to 4 p.m. daily except Mondays and holidays; reservations are suggested for weekends and required for groups. Call 724-452-7341 or 888-821-4822, or visit the Web site, www.harmonymuseum.org.

<B>Pittsburgh Children's Museum</B>, 10 Children's Way, Allegheny Square, hosts the traveling exhibit "Exploring Trees Inside and Out" through May 17. Regular museum hours are 10 a.m. to 5 p.m. Mondays to Saturdays; and noon to 5 p.m. Sundays. Admission is $9 for children 2 to 18 and senior citizens and $10 for adults; children younger than 2 are admitted free. Call 412-322-5058 or visit the Web site, www.pittsburghkids.org.<B>Carnegie Museum of Natural History</B>, 4400 Forbes Ave. in Oakland, hosts "Dinosaurs in Their Time." 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. Closed major holidays. Through Friday, all children's admissions are half-priced at $5.50 per child ages 3 to 18. Regular admission, which includes the Carnegie Museum of Art, is $15 for adults, $12 for senior citizens, and $11 for students and children age 3 and older, and free for members and children younger than 3. Call 412-622-3131 or visit the Web site, www.carnegiemnh.org.<B>Carnegie Science Center</B>, One Allegheny Ave., North Side, has opened the Guitar Hero Electric Lounge, featuring eight giant screens, a concert-quality sound system and lighting effects, running from 8 p.m. to midnight Saturdays in March. Tickets for the Electric Lounge are $8. Science Center visitors also can explore the popular musical video game every Saturday from 5 to 7 p.m. during the Guitar Hero Jam Session, which is free with general admission. Regular hours are 10 a.m. to 7 p.m. Fridays and Saturdays and from 10 a.m. to 5 p.m. Sundays through Thursdays; closed holidays. Admission is $14 for adults and $10 for senior citizens 62 and older and children 3 to 18. Parking is $3. Call 412-237-3400 or visit the Web site, www.carnegiesciencecenter.org.<B>Phipps Conservatory and Botanical Gardens</B> in Schenley Park is open daily from 9:30 a.m. to 5 p.m. and until 10 p.m. on Fridays. Admission rates are $10 for adults, $9 for seniors 62 and older and students with ID, and $7 for children 2 to 18. Phipps members and children under 2 are admitted free. Call 412-622-6914 or visit www.phipps.conservatory.org.<B>Heinz History Center</B>, 1212 Smallman St., features "Pittsburgh: A Tradition of Innovation," tracing Western Pennsylvania's imprint on the world. Hours are 10 a.m. to 5 p.m. daily, except holidays. Admission is $9 for adults, $7 for senior citizens older than 61, $5 for students with ID and for children 6 to 18, and free for children younger than 6. Call 412-454-6000.