Old Stone House will be the site of a Native American Powwow from 9 a.m. to 6 p.m. Saturday and Sunday. Dancing, storytelling, tomahawk throwing and falconry will be part of the free entertainment provided by People of the Forest and All Nations Gathering. Traditional powwow drums will be played by the Muddy Creek Singers. Vendors will be demonstrating bead work and displaying numerous crafts, jewelry and clothes found in Native American societies. The Old Stone House is at the intersection of Routes 8, 173 and 528. Call 724-738-4964.

Harmony Museum on Mercer Street in Harmony, offers 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., 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. 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>National Aviary</B>, 700 Arch St., hosts International Migratory Bird Day — Destination Pittsburgh from 11 a.m. to 2 p.m. Saturday. Activities are free with admission, which is $10 for adults; $9 for senior citizens; $8.50 for children ages 2 to 12; and free for children younger than 2. Regular hours are 10 a.m. to 5 p.m. daily. Free admission is offered on Mother's Day for mothers and grandmothers. Call 412-323-7235 or visit the Web site, www.aviary.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 ages 6 to 18, and free for children younger than 6. Call 412-454-6000.

<B>Old Economy Village</B>, Route 65, Ambridge, will open a new exhibit "Harmony in Wood: The Furniture of the Harmony Society" from 9 a.m. to 5 p.m. Saturday. The Pennsylvania Historical and Museum Commission is offering free admission that day. The exhibit will be open during regular site hours from 9 a.m. to 5 p.m. Tuesdays through Saturdays and noon to 5 p.m. Sundays. Admission will be charged after Saturday. Call 724-266-4500 or send an e-mail to: ra-oldeconomy@state.pa.us.