Before the summer grinds to a halt, you can take advantage of some two-day activities over this three- day weekend.

On Saturday and Sunday afternoon, you can observe the art of making whiskey in a demonstration at Catoctin Mountain Park in Thurmont, Md. Or you can head down to Colonial Williamsburg's 18th-Century Festival loaded with games, fiddlers, food booths, craftsmen, auctions and a special military encampment.

And on the third day, Kensington celebrates Labor Day with a parade and festival.

Admission to the following activities is free unless otherwise noted.

SENIOR CITIZEN PARTY -- Friday, 10 a.m. to 2, Good Luck Community Center, 8601 Good Luck Rd., Lanham. Dancing, ceramics, exercise and needlework. Bring a lunch and a friend. 552-1093.

OLD TOWN TOUR -- Friday, 8 p.m.; Saturday, 10:30 a.m., 8 p.m.; Sunday, 2, Ramsay House Visitors Center, 221 King St., Alexandria. Take a special summer tour retracing the steps of George Washington and Robert E. Lee with a colonial-attired guide through the cobblestoned streets of Old Town Alexandria. Adults $2; ages seven to 15, $1. 548-0100.

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, "The Georgetown." Take a mule-drawn boat ride down the C&O Canal. Adults $4; children and seniors $2. 472-4376.

18TH-CENTURY TOWN FAIR -- Saturday and Sunday, 9:15 to 6 p.m., Market Square, The Duke of Gloucester Street, Colonial Williamsburg, Williamsburg, Va. (take I-95 to Rte. 64 east to Williamsburg; follow signs to historic area exit). A two-day, outdoor festival, featuring games, music, a military encampment, 300 re-enactment soldiers, music, dance, crafts, theater, food and more. 804/229-1000.

MOONSHINING DEMONSTRATION -- Saturday and Sunday, 11 to 5, Catoctin Mountain Park, Thurmont, Md. (take I-270 north to U.S. 15 north and then Rte. 77 west which leads into the park; park at visitors center). A park ranger gives a continuous whiskey-making demonstration at the actual site of the Blue Blazes Whiskey Still. 301/663- 8687.

JEWISH FESTIVAL -- Sunday, noon to 10, Monday, noon to 8, Festival Hall, Pratt and Sharp streets, Baltimore (take Baltimore- Washington Expressway exiting on Pratt Street; go right three blocks, hall is to the right), "10th Annual Jewish-American Festival." A two-day festival showcasing Jewish life with continuous music, dance, food, film festival, special salute to Al Jolson, exhibit of religious ceremonial artifacts and more. 301/837-4636.

WILDFLOWER BIKE HIKE -- Saturday, 2 to 4, Sunset Hills Railroad Station, near intersection of Old Reston Avenue and Sunset Hills Boulevard, Reston. Take a two-hour bike ride with a park naturalist; bring a bike and wildflower guide, if you have one. For reservations and more information call 528- 5406.

CIVIL WAR MILITARY PROGRAM -- Sunday, noon to 5, Fort Washington Park, Maryland side of Potomac River (from Beltway, take Indian Head Highway south for four miles; turn right on Fort Washington Road to fort). Volunteers demonstrate weapons and garrison activities; tours of the fort given at 1 and 3. 301/292-2112.

TREE HIKE -- Sunday, 1, Nature Center, Prince William Forest Park, near Quantico, Va. (take I-95 to Rte. 619 west; park entrance 1/2 mile on right, follow signs to nature center). Join a ranger for a hike to become more familiar with trees at the park. 703/221- 2104.

CANDLELIGHT TOUR -- Sunday, 6 to 8, Smallwood's Retreat, Smallwood State Park, Rte. 224, Marbury, Md. (take Rte. 210 south 19 miles to Rte. 225 for one mile; make right on Rte. 224. Follow signs; park entrance is 2 miles on right). Visit the restored 18th- century home of General William Smallwood during a candlelight tour. 301/743-7613.

LABOR DAY PARADE AND FESTIVAL -- Monday, 10 to 4, St. Paul Park and Howard Avenue, Kensington (take Connecticut Avenue straight out past the Beltway into Kensington, make right onto Howard Avenue; find parking around side streets because Howard Avenue will be blocked off), "18th Annual Labor Day Parade and Festival." A parade kicks off the day, followed at noon by music, exhibits, puppets, merchants, craftsmen, antique vendors and more. 949- 2800.

INTERNATIONAL FOOD FESTIVAL -- Monday, 3 to 9, Good Shepherd Catholic Church, 8710 Mount Vernon Highway, Mount Vernon, Va. (take the George Washington Memorial Parkway south toward Mount Vernon, make first right at the stop sign at Mount Vernon Plantation; church is one mile on the left). From Polish sausages to tacos and Korean beef, sample a wide variety of international foods (including desserts). There'll also be a yard sale, games and a raffle. 780-3726.

LABOR DAY ICE SKATE -- Monday, 6 to 10, Mount Vernon Recreation Center, 2017 Belle View Blvd., Alexandria (take Beltway Exit 1-S south bearing right onto Ft. Hunt Road for 11/2 miles to a right at Belle View Road; park entrance on left). Adults can take an evening off for an adults-only skate during an extended four-hour session. Admission $3.50; skate rental $1.25. 768-3224.