Keystone N-Trak Model Railroad Club Model railroad club open house. Burholme Baptist Church, 905 Cottman Ave.; 215-745-3483. www.keystonentrak.us. Donations accepted. 5/17 noon-4 pm. 5/18 1-5 pm.
*FREE* Old City Stroll & Sidewalk Sale Bargains, food & more. Rain date 5/18. Old City, Between Front & 5th; 215-440-7000. www.oldcity.org. 5/17 11 am-6 pm.
*FREE* Philadelphia Book Festival Appearances by 60 prominent authors (including Barbara Walters), book talks, live music, children's entertainment, exhibitors & more. Free Library of Philadelphia, 1901 Vine St.; 215-686-5372. www.library.phila.gov. 
5/17 11 am. 5/18 11:30 am.
*FREE* Philadelphia Cares About Fairmount Park Day Help plant flowers, remove vines & clean up winter debris. Fairmount Park, 4231 N. Concourse Dr.; 215-564-4544. www.gpcares.com. 5/17 9 am-noon.
Antique Car Show & Flea Market Over 250 antique cars & family-friendly activities. Linvilla Orchards, 137 W. Knowlton Rd., Media; 610-874-4678.
www.spokenwheel.com. 5/18 9 am-4 pm.
Bucks County Irish Festival Irish music & dancing, with craft & food vendors. Polanka Park, 3258 Knights Rd., Bensalem; 215-331-4636. $10; free for children under 12. 5/18 12:30-6 pm.
*FREE* Chester County Hospital May Festival Rides, carnival games, entertainment, fair food & more. Goshen Country Fairgrounds, 1320 Park Avenue, West Chester; 610-738-2832. www.cchosp.com/mayfest. 5/16 5-11 pm. 5/17 10 am-11 pm. 5/18 10 am-7 pm.
*FREE* The EDSites.net Pride Parade Featuring appearance by Gov. Edward Rendell. New Hope Celebrates Pride event. New Hope-Solebury High School, 180 W. Bridge St., New Hope; 215-862-2028. www.newhopecelebrates.com. 5/17 11 am.
