Old Stone House at the intersection of routes 8, 528 and 173 will be the site of a Civil War weekend from 10 a.m. to 5 p.m. Saturday and Sunday. The free event is hosted in conjunction with the 10th PA Reserves "Mercer Rifles" re-enactment group. Activities include a living history encampment, soldier competitions, battle re-enactments and demonstrations of Civil War camp life including cooking, blacksmithing, children's games and music. The Old Stone House will be open for guided tours, and refreshments will be available. Call 724-738-4964 or visit www.oldstonehousePA.org.

Harmony Museum on Mercer Street in Harmony is open from 1 to 4 p.m. daily; closed 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>Phipps Conservatory and Botanical Gardens</B> in Schenley Park will transform its Stove Room into a butterfly forest, featuring various species of butterflies flying among the flowers and foliage, beginning Saturday and continuing through Sept. 6. Phipps is open daily from 9:30 a.m. to 5 p.m.; Fridays until 10 p.m. Admission is adults, $12; seniors 62 and older and students with valid ID, $11; children 2 to 18, $9; children under 2, free. For more information, call 412-622-6914 or visit phipps.conservatory.org<B>National Aviary</B>, 700 Arch St., is hosting Earth Day activities today and a party for the planet from 11 a.m. to 2 p.m. Saturday. Regular hours are 10 a.m. to 5 p.m. Mondays through Saturdays and noon to 5 p.m. Sundays. Admission is $12 for adults; $11 for senior citizens; $9.50 for children ages 2 to 12; and free for children younger than 2. Call 412-323-7235 or visit the Web site, www.aviary.org.<B>Pittsburgh Children's Museum,</B> 10 Children's Way, Allegheny Square, presents the exhibit "Yinz Play!" through June 6. Regular hours are from 10 a.m. to 5 p.m. Mondays to Saturdays; and noon to 5 p.m. Sundays, except holidays. Admission is $11 for adults; $10 for senior citizens older than 65 and children ages 2 to 18, and free for children younger than 2. Parking is $5 for non-members. Call 412-322-5058 or visit the Web site, www.pittsburghkids.org.<B>ToonSeum</B>, Pittsburgh's Museum of Cartoon Art at 945 Liberty Ave., hosts "The Art of AKIRA" from May 8 to July 18, about the film by Katsuhiro Otomo. This is the largest collection of AKIRA production art ever displayed to the public and was culled from more than 10,000 pieces of original production art from the private collection of guest curator Joe Peacock. An opening party will be held from 7 to 10 p.m. May 7. Tickets are $25 for non-members and free for ToonSeum members. Regular museum hours are 10 a.m. to 3 p.m. Wednesdays and Thursdays, 10 a.m. to 5 p.m. Fridays and Saturdays and 11 a.m. to 4 p.m. Sundays, except holidays. Museum admission is $4 for adults and $3 for children ages 5 to 17; children younger than 5 are admitted free. Visit the Web site, www.toonseum.org.<B>Heinz History Center</B>, 1212 Smallman St., continues through July 18 "Discover the Real George Washington: New Views from Mount Vernon," an exhibition from George Washington's Mount Vernon Estate & Gardens. The exhibition features highlights from Mount Vernon's collection and provides a new perspective on Washington, his achievements and legacies. Visitors can view nearly 100 objects, including full-scale figures of Washington, architectural models, decorative and fine art items, maps, manuscripts and paintings. Center hours are 10 a.m. to 5 p.m. daily, except holidays. Admission is $10 for adults, $9 for senior citizens age 62 and older, $5 for students with ID and for children ages 4 to 17, and free for children 3 and younger. Call 412-454-6000.<B>Carnegie Science Center</B>, One Allegheny Ave., North Side, hosts "King Of Pop," a 45-minute laser show synchronized to the music of Michael Jackson, regularly at 9 p.m. Fridays and Saturdays. Weekday matinees are shown at 3 p.m., while Saturday and Sunday matinees start at 1 and 3 p.m. Center 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. Regular admission is $17.95 for adults and $9.95 for children ages 3 to 12; admission is discounted for senior citizens on Tuesdays. Parking is $5. Call 412-237-3400 or visit the Web site, www.carnegiesciencecenter.org.<B>Carnegie Museum of Natural History</B>, 4400 Forbes Ave., Oakland, continues the traveling exhibition "Whales/Tohora" through May 2. 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. Closed major holidays. Admission, which includes the Carnegie Museum of Art, is $15 for adults, $12 for senior citizens, and $11 for students with ID and children ages 3 to 18, and free for members and children younger than 3. Call 412-622-3131 or visit the Web site, www.carnegiemnh.org.