Fair Time in Frederick

The 143rd Great Frederick Fair kicks off at 5 p.m. tomorrow, offering carnival rides, horse shows, tractor pulls, a demolition derby, a wagon parade, potato sack races, scarecrow making and a kids' day, through Sept. 24. Admission varies depending on the day and event. 797 E. Patrick St., Frederick. 301-663-5895 or www.thegreatfrederickfair.com.

'Symphonic Blockbusters'

The National Philharmonic presents "Symphonic Blockbusters," a four concert series that opens Saturday and runs through May 20. Saturday's concert includes Mozart's overture to "The Marriage of Figaro" and Piano Concerto No. 20 and Beethoven's Symphony No. 7. Conductor Piotr Gajewski leads the symphony, with pianist Christopher Taylor. 8 p.m. Music Center at Strathmore, 5301 Tuckerman Lane, North Bethesda. $25-$80; children 17 and younger, free. 301-581-5100 or www.strathmore.org.

Celebrate Gaithersburg

Gaithersburg hosts the Celebrate Gaithersburg in Olde Towne street festival, featuring entertainment, international food, arts and crafts, children's activities and interactive displays, from 11 a.m. to 4 p.m. Sunday. At the corner of Summit and Diamond Avenues, Gaithersburg. Free. 301-258-6350 or www.gaithersburgmd.gov.

The Celebrate Gaithersburg street festival features performers, crafts and international foods. The event runs from 11 a.m. to 4 p.m. Sunday at Summit and Diamond Avenues.