In Maryland, a few towns commemorate the long weekend with festivals and parades, such as the GREENBELT LABOR DAY FESTIVAL beginning Friday at 7 p.m. and continuing through Monday. It's at the Center Shopping Mall beside the Greenbelt Municipal Building, with rides, games, community booths, stage events, athletic contests and children's activities. Free admission. Call 474-1518 or 345- 8105.

Also marking the day is the 14th annual KENSINGTON LABOR DAY PARADE AND FESTIVAL. That's 10 to 4, starting at St. Paul and Plyers Mill roads. Following is a flea market with arts, crafts and antiques, plus games going all day on Howard Avenue. Free. Call 949-2424.

And the 44th annual GAITHERSBURG/WASHINGTON GROVE LABOR DAY PARADE Monday is 11/2 miles long, featuring marching bands, majorettes and antique autos -- prizes follow for the "Best of" in each category. Begins at 1 at the corner of East Diamond Avenue and Girard Street; the reviewing stand is on the grounds of the Asbury Home on Russell Avenue.

The MARYLAND STATE FAIR continues through Labor Day, daily 10 to 10. The Timonium Fair Grounds in Baltimore County, Maryland has horse races, carnival rides, games and concessions. Admission, $2 adults; under 12, free. Additional $1 fee to enter races. Call 301/252-0200.

At Lilypons Water Gardens they're holdinng the first KOI CELEBRATION, Saturday to Monday 11 to 5 daily. Besides the exotic Japanese fish, there are tours for birdwatchers, the music of concert bands and choirs, children's theater, karate exhibitions and crafts and refreshments for sale. Free admission. For details or directions, call 301/662-2392.

Musicians celebrate the workers who built the C&O Canal Monday with an ETHNIC MUSIC CONCERT. It's free at 3 at Great Falls Tavern, Maryland. Call 299-3613.

If you want to celebrate the canal itself, try riding the CANAL CLIPPER BARGE, Friday and Saturday at 10:30, 1 and 3; Sunday and Monday additional evening rides at 5. That's at Great Falls Park; admission is $1.75 for over 60 and under 13, all others, $3.25, and tickets go on sale, first come, first served, two hours before each ride. Call 299- 2026.

More music can be heard at the continuing CHAUTAUQUA CONCERT SERIES, Sunday at 2 and 3:15 in Glen Echo Park's Bumper Car Pavilion. Jazz and swing are free to hear at the park on MacArthur Boulevard. Call 492-6282.

In that neck of the woods, more artists show off in the 12th annual GLEN ECHO ART SHOW. The show is Saturday through Monday, noon to 6 in the Spanish Ballroom Free to see; for information, call 492-6282.

Crisfield celebrates with a HARD CRAB DERBY AND FAIR, starting with the Miss Crustacean beauty pageant Friday night and continuing through Sunday with a grand finale of fireworks at 10. Also going on are a Governor's cup (they race crabs), a crab-cooking contest, band concerts and a carnival. Admission is $2, $1 for children. Call 301/968-2682.

Lots of music at the VFW. FESTIVAL OF BANDS, Sunday at noon. It's at VFW Post 8950 on 9800 Good Luck Road in Lanham. Admission, $2, benefits the Muscular Dystrophy Association. Call 459-4775.

Sporty goings-on include the PVDA HORSE SHOW AND CRAFTS FAIR Saturday and Sunday, 10 to 6, which features dressage. 150 horses compete at the Prince Georges Equestrian Center, and there are handicrafts, music, food and games as well. Free admission. Call 789-3004.

More games with horses are at the POTOMAC POLO CLUB Sunday at 4, when the home team plays the Middleburg Polo Club at the corner of River and Hughes roads in Potomac. Admission: $2 per person; $5 per carload; $10 fieldside. Call 983-1555.

There's HARNESS RACING at Freestate Race Track, Friday and Saturday at 7:45 and Sunday at 6:15. At 9342 Washington Boulevard (Route 1), Laurel. Admission: $2, grandstand; $4 clubhouse; parking, $1. Call 725-2600.

A SOFTBALL MARATHON guarantees insomniacs some live action all weekend. It begins Friday at 7 and continues until Sunday at 7 at Long Field (intersection of Maryland routes 424 and 3 in Crofton). All proceeds to benefit Muscular Dystrophy. Call 793-3968 or 261-0364.

This weekend is the time to stock up for winter; try a few craft sales and flea markets. The BETHESDA ELEPHANT SALE is Monday, 9:30 to 1 at Congregation Beth El. Free admission at 8215 Old Georgetown Road. Call 770-2625.

To benefit the Chesapeake Bird Sanctuary there's a FLEA MARKET there on Saturday. It's 10 to 3 at Holy Rosary Church, Rosaryville Road and Route 301, Upper Marlboro. White elephants, antiques, furniture, kitchen items and clothing. Free. Call 372-6416. ROSECROFT RACEWAY FLEA MARKET is Sunday, 10 to 5. Free admission at 6336 Rosecroft Drive in Oxon Hill, Maryland; offerings include arts, crafts, antiques and games. Call 567- 4220.

Or how about a sock hop? That's at the CALVERT COUNTY COFFEE BREAK, Friday to Monday at King's Antique Village, Route 301 (five miles north of Upper Marlboro). The marathon weekend to benefit MDA also features an antiques auction, country music, dancing and raffles. Festivities start Friday at 8 with the Reivers Band. Free. Call, 855-5575 or 971-1179.

At WILD WORLD, fireworks end each evening of the long weekend; daily hours are 10 to 10 and the Spinners play Sunday at 6 and 8; included with the price of admission to the amusement park at 13710 Central Avenue in Largo. Call 301/249-1500.