Old Stone House will be the site of tours from 10 a.m. to 5 p.m. Saturdays and noon to 5 p.m. Sundays through October. Halloween and perhaps Christmas events will be planned. Admission is free, but donations are accepted. The house at the intersection of Routes 8, 173 and 528, 12 miles north of Butler, is owned and operated by Slippery Rock University. Call 724-738-4964 to confirm hours or make reservations for private tours.

Harmony Museum, representing the town founded in 1804 by pacifist German Lutheran Separatists and their Harmony Society, will celebrate an Oktoberfest German dinner in its Stewart Hall, 218 Mercer St., Saturday. In addition, the Museum Shop at 222 Mercer St. will offer a weekend sale of seasonal items. The buffet includes traditional German fare, and coffee and tea for those who don't take their favorite German beverage. Cost is $15 per person, with proceeds benefiting museum operations. Reservations are required for either of two seatings, at 4:30 p.m. and 6:15 p.m., and can be made with the museum office at 724-452-7341.

<B>National Aviary</B>, 700 Arch St., will host Owl-O-Ween from 10 a.m. to 1 p.m. Saturdays in October, featuring Halloween treat bags, candy, crafts and plenty of interactive activities with the Aviary's birds. There will be free admission on Oct. 31 for children in costume. FliteZone moves inside for a new show running from 11 a.m. to 1:30 p.m. Wednesdays through Sundays beginning Saturday. Hours are 10 a.m. to 5 p.m. daily except Christmas Day. Regular admission is $9 for adults; $8 for senior citizens; $7.50 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>Heinz History Center</B>, 1212 Smallman St., in celebration of Pittsburgh's 250th birthday is displaying "Pittsburgh At 250," honoring the region's historic anniversary celebrations in 1858, 1908, 1958 and 2008. Each section includes artifacts and documents from the anniversary celebration set against a panoramic view of the city from that time period. Featured artifacts include commemorative medals, souvenirs, programs and special publications. The display will continue through early 2009. 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.