If you're bummed out because all our friends are beached on some Greek island, don't worry. You've a free ticket to exotica at this Saturday's "1985 International Festival: A Passport to the World," held at Western Plaza on Pennsylvania Avenue. The day features African storytelling, martial arts from Brazil, along with food, music, arts and crafts and other cultural goodies from many Asian, Caribbean, European and South American countries. The event is free, with the rain date scheduled for Sunday.

Admission to the following activities is free unless otherwise noted.CANAL TOUR -- Wednesday-Sunday, 10:30, 1 and 3; an additional tour Saturday and Sunday at 5, C&O Canal National Historical Park, The Foundry Mall, 1055 Thomas Jefferson St. NW. Take a mule-drawn boatride aboard "The Georgetown" down the C&O canal. Adults $4; children and seniors, $2.

COUNTRY FAIR -- Saturday and Sunday, 10 to 7, Luckett's Community Center, on U.S. 15, eight miles north of Leesburg (take Beltway to Rte. 7 west toward Leesburg; go north on U.S. 15), "Lucketts Fair." Two days of old-time entertainment, music, cake walks, petting zoos, pony rides, log cabin tour, craft demonstrations, bazaar, country food and much more. $1 adults; children under six, free. 703/777-8881.

INTERNATIONAL FESTIVAL -- Saturday, 11 to 7:30, Western Plaza, 1300 Pennsylvania Ave. (in front of the National Theater), "A Passport to the World." Experience different cultures of the world through food, entertainment, arts and crafts and more. 369- 1466.

SECOND BATTLE OF MANASSAS -- Saturday, noon to dusk; Sunday, 11 to 4, Ben Lomond District Park, Ben Lomond Park Drive, Sudley Manor Drive, off Rte. 234, Manassas (take I-66 west to Rte. 234, exiting on Sudley Road; make left on Sudley Manor Drive. Park located at end), "Second Battle of Manassas Reenactment." Two days of authentic Civil War battles, military displays, antique auctions, regimental bands, fireworks, hot-air balloon rides and more. $2 per car parking fee. 703/361-7126.

FORT FREDERICK GARRISON -- Saturday and Sunday, 1 to 4, Fort Frederick State Park, Big Pool, Md. (Take Beltway to Rte. 270 north to Rte. I-70 west; follow signs to park). Catch an authentic glimpse of 18th- century garrison life; marching, drilling, combat training, food, historical items and more. 301/269-3761.

WATER BIRDS -- Saturday, 7 to 8:30, Huntley Meadows Park, Harrison Lane and Lockheed Boulevard, Hybla Valley, Va. (take Beltway Exit 1-S 31/2 miles to Lockheed Boulevard, make right; park entrance on the left at Harrison Lane). Join a naturalist on the lookout for herons, bitterns, rails, grebes and other wetland birds; bring binoculars and field guides. 768-2525.

QUILT SHOW -- Sunday, 11 to 5, Sully Plantation, Chantilly, Va. (take I-66 west and follow signs to Dulles Airport, then take U.S. 28 north, Sully Road, and follow signs to the Sully Plantation). "10th Annual Sully Quilt Show." Expert quilters, suppliers and antique quilt dealers will be on hand to answer quilting questions, demonstrate the art and appraise quilts; kids and adults can also try their hand with a needle; and food will be for sale. Adults $3; children under 16, $1. 437-1794.

WILDFOWL CARVING -- Sunday, noon to 4, Sweden Point Marina, Smallwood State Park, Rte. 244, Marbury, Md. (take Rte. 210 south 19 miles to Rte. 225 for one mile; make right on Rte. 224. Follow signs; park entrance two miles on right). See the art of wildfowl carving; bring a picnic lunch and go fishing at the marina. 301/743-7613.

BALTIMORE COUNTY DAY -- Sunday, 1 to 4, Ladew Topiary Gardens, 3535 Jarrettsville Pike, Monkton, Md. (take Baltimore Beltway exit 27 north 14 miles to Rte. 146; follow to gardens). View antique automobiles and tour well-groomed grounds featuring gardens and sculptured hedges. Adults $4; Baltimore County residents, $2.50; children and seniors receive further reductions. 301/557-9466.