Hayrides are supposed to be nostalgic and romantic, right? What could be more fun than bundling up in your long undies and setting out for a bumpy ride upon a hay bale in the crisp autumn air, singing old campfire songs like, "The Ants Go Marching One By One, Hurrah, Hurrah," feeling your nose run, then endint up back at the barn for hot cider of chocolate? Ah, what good old-fashioned fun! Remember when you asked that darling freshman to your college fraternity's hayride party just for the chance to snuggle up with her in the hay -- and she ended up sneezing all night? Or how about when your church choir pals kept pushing you off the hay wagon -- and into what the horses had left behind? This is the season of pumpkin moons, leaves to be raked, and yes, hay down your back.

If you want to bing back those memories or you've always wondered if hayrides are really like what they look like in the movies, Potomac Equitation Farm in Centreville, Va. swings open its gates Saturday, October 10 for a good ol' country hayride and buffet. They'll even throw in a large pumpkin moon for free. (Lucky for them, the actual full moon arrives during the next week, promising a near-full moon for the 10th, and if need be, for their rain date of October 17.) Most hayride places require you to bring the large group, but for this party, owner Jackie Novak brings the group together. Last year 180 people showed up for the hayride and feed; she expects 100 to 200 this year. The farm lays out a country buffet on candle-lit tables with barbecued chicken, casseroles, baked beans, potato salad, homemade cakes and pies a la mode, soft drinks and "exotic" punch. They're also providing corn fritters made "on the spot" with butter, honey and jams and hot mulled cider for after the hayriding.

The hayrides are of the traditional horse- drawn wagon type, four horses to a wagon, and will haul 50 people at a time through 160 acres of open fields brimming with yellow wildflowers. Novak warns that it's always cold when there's a full moon so she's providing a warm fire in her big stone barn after the rides. The party begins at 5, and is $15 for adults and $8 for children. Reservations must be made by October 7. The price includes two hayrides and food.

Children get an additional treat -- their price includes unlimited pony rides until 10. Adults can take out Potomac's horses unguided until dark, in lighted rings until midnight or on guided moonlight rides for $9 an hour.

POTOMAC EQUITATION FARM, 5320 Pleasant Valley Road, Centreville 22020. 703/631-9720. Take I-66 west to Centreville-Route 28 exit. Right into Centreville to first light. Turn right onto U.S. 29 to Pleasant Valley Road (about 21/2 miles). Right onto Pleasant Valley Road about 3 miles to entrance gate on left. The farm will also do tractor-drawn hayrides for smaller groups and horse-drawn rides for larger groups and will provide buffet dinners. Price depends on the size of group and food served.

OTHER WAGONS, SAME OLD MOON

If you've already rounded up your own large group, a number of local farms still offer hayrides to hearty souls:

BRANDYWINE STABLES Route 4, Box 69, Brandywine, Maryland. 372-8914. Take Beltway exit 7A (Branch Avenue-Waldorf) 12 miles to stables. Brandywine has by far the most interesting barnyard menagerie and offers the most authentic hayride for your money. If you arrive before dark, you'll be able to see the stable's "farm" animals -- zebra, buffalo, camels, ostrich, Texas longhorn cattle, yaks and others -- wandering around the open field. Brandywine hitches up four-horse teams to its red farm wagons loaded with hay and complete with sleigh bells. The horses are Belgians, larger than your average mount, and weigh 2,200 pounds each. The hayride lasts about two hours with a bonfire stop mid-trail. Brandywine has four wagons, each with a four-horse team, and sometimes runs six or seven hayride groups a night. But the farm covers 600 acres of woods and open fields, so you won't necessarily have to hear the other groups' silly campfire songs. A minimum of $100 is charged for 25 people -- $4 each additional. Brandywine also has a big loft in its new barn that is available for dances and parties.

LUX STABLES, 10214 Lanham Severn Road, Lanham, Maryland 20706. 464-2574. Take Beltway exit 20A (Route 450) and go left on Route 564, two miles to the first white fence on the left. Lux offers a double- treat hayride: It will pick up your group (up to 50 people) anywhere in the metropolitan area and haul you back to the farm in a 28-foot enclosed truck filled with hay. (You can peek through the slats in the sides of the truck and moo at the passing traffic.) At the farm the "official" hayride will run continuously with about 20 people at a time on a flatbed wagon pulled by a tractor. Lux also provides a bonfire while you're waiting your turn for a ride. The farm covers 28 acres of open fields, and the ride takes only about 20 minutes. Then if you haven't had your fill of hay, they'll load you back into the big truck for the drive back into town. Lux charges a minimum of $150 for 50 people and has an additional truck and tractor for larger groups.

PARKVIEW STABLES, 16009 Lee Highway, Centreville, Virginia 22020. 830-3754. (Four miles west of Centreville on U.S. 29-211.) Parkview runs its tractor and haywagon for groups of 20 at $3 per person, but can fit about 35 if everyone snuggles up tight. The hour to 11/2-hour ride is over 90 acres of wooded and open country and ends at a campsite near the Bull Run River, where Parkview sets up a bonfire for cookouts. You can also camp overnight at this site for $5 per person extra. Parkview also has a barn available for parties.

PISCATAWAY STABLES, Box 625, Piscataway Road, Clinton, Maryland 20735. 297-7808. Take Beltway exit 7A (Branch Avenue-Waldorf) seven miles to Piscataway Road (Maryland 223); go three miles to the first blacktop driveway on the right after Hyde Airport. Piscataway pulls its wagon full of hay by tractor through more than a hundred acres of woods and open fields. Its wagon holds 30 people and is $90, $3 for each additional person. The farm generally runs two 40-minute rides and builds a bonfire in between. Piscataway says it'll gladly cart your coolers and supplies out to the bonfire to meet you.

CAMP WARADACA, 4015 Damascus Road, Gaithersburg, Maryland 20879. 924-4991. Five miles north of Olney, on Georgia Avenue (Route 97). Take a left on 650, go one mile to camp. Camp Waradaca has about 80 horses on its 230 acres, but its two hayride wagons are pulled by tractors. The camp charges $50 a wagon on weekends, $40 during the week; each wagon holds 30 to 40 people. The ride in the hay lasts about an hour and the camp has a bonfire after the ride. This bargain rate must be popular -- the camp says weekends are pretty well booked up until December, but there's plenty of room during the week.