Food served Sunday through Thursday 11 a.m. to 1 a.m., Friday 11 a.m. to 1 a.m. and Saturday 11:30 a.m. to 1 a.m. (Brunch served Sunday 11 a.m. to 3 p.m.) AE, CB, D, MC, V. Prices: Most snacks and entrees $4 to $8.

Jaspers is a big, smooth, snazzy watering hole in the California mod style that's been somehow plunked down in

the middle of a parking lot in a Greenbelt shopping center. Packed to the walls almost every night, it's a mecca

for Prince George's County singles looking for other Prince George's County singles. So Jasper's offers a social phenomenon to be observed as well as a meal to be eaten. Here's a chronicle of our first visit:

Eight o' clock on a weekend night. We try our best to melt into the young crowd of suburban singles obediently queuing up at the door like so many polite salmon waiting to head upstream. After an hour of sipping on the patio, our names are called, and we find ourselves perched at a small table with a good view of the huge, multi-angled room. Like anthropologists on a field trip, we watch the singles, jammed six-deep at the immense central bar, as they mingle, drink, play backgammon, scout the terrain.

We gradually acclimate to the background noise, which is loud enough to make a foundry foreman wince. The cacophony, punctuated regularly by "Your table is ready" announcements on the p.a. system, takes us back to Greyhound stations during Christmas holidays. A waiter shouts in our ear that Jasper's serves a thousand people a night. We suspect him of understatement.

As it grows later, the din increases, the crowd seems to get younger, and our eyes begin to cloud over. The mirrors on the wall make the already cavernous room seem even bigger, in the confusion of space. Our minds drift into fantasy. Is this the kind of sensory overload that causes laboratory mice to eat their young? Have we somehow wandered into a sci-fi movie in which everyone under 20 and over 35 has been made to disappear? Are they checking IDs at the door so a middle-aged person can't sneak by? Do elderly couples in the parking lot ask for the college kids in line to buy them liquor?

We force ourselves back to reality. There's serious work to be done. The menu, bound in a spiral notebook like some culinary term paper, runs to 24 pages and contains over a hundred items. There are pages to be turned, and decisions to be made. We order, we eat, we wander. We watch others are eating. Later we make two more visits to Jasper's, to sample more and confirm initial impressions.

Here's the result, recollected in tranquility.

Much of the food at Jasper's, especially considering the formidable logistics of serving that many people, is remarkably good. Portions are big, prices reasonable. Service is unfailingly friendly and helpful, if often slow. The wine list is short but intelligently chosen. Look for the Beaulieu Vineyards cabernet sauvignon, big, smooth and woody. Or the Piesporter Goldtropfchen, a medium-sweet mosel that's velvet in a bottle.

Most of the menu leans toward snacks and light meals, and that's the direction you should probably lean, too. The hamburgers, in 13 varieties, are beautiful behemoths -- nine ounces of good beef, cooked juicy and just as ordered. Fried jumbo shrimp are nearly as impressive. (But "peel and eat" shrimp are disappointingly bland and can suffer from a touch of mushiness.) Fried artichokes are feather-light, a first-rate nibble. But the onion rings are encased in so durable an armor of batter they could probably serve well in a game of ring-toss.

A couple of good general rules at Jasper's: (1) If it's a baked potato or any part thereof, order it. The stuffed potato skins are top-notch, and the baked potatoes themselves, free of mummification in foil, are works of art. (2) If it sounds Mexican, it's a good bet. That includes the various nachos permutations, and especially the "Mexican pizza," with chunks of real tomato, rough-ground beef, and good jalape?no peppers. Steak and chicken on sticks also seem to be big sellers, and with good reason. Available as appetizers or entrees, they're well trimmed, well marinated, and well broiled over charcoal.

But not all the light meals succeed. The turkey-bacon pita sandwich, for example, is a singularly textureless and doughy disc of pita bread filled mainly with lettuce and tomato. We also had relatively poor luck with the more dinnerish items we tried.

Chicken Jasper's, an unremarkable bird of dryish breast, is basted in a bland barbecue sauce. Spinach and feta pie is a flavorless bore, with the wettest of filo pastries. And the fettucine primavera, a poor relation if there ever was one, seems a close cousin to luncheonette macaroni and cheese.

Desserts are mainly excellent: a flawless apple pie in a casserole, with firm fruit and plenty of cinnamon, served with ice cream; a superlative carrot cake, with walnuts, coconut and a good cream cheese frosting; and a peanut butter pie that tastes infinitely better than it sounds. (But the super-chocolate creations are a let-down, with ordinary brownies and fudge sauce, and thin, gassy "whipped cream.")

Now for the big dilemma. Suppose you want to sample Jasper's food without the singles scene? To eat rather than meet, in others words. One possibility is to go early on a weeknight. But the menu advertises "unwind time" at the bar beginning at 3 p.m., so that option may not guarantee tranquility. (Who can afford to unwind at three in the afternoon? Some of us have barely gotten to work.)

A better choice might be Sunday brunch. In the light of day, the dining room can be seen for the handsome place it is, and, without the frenzy of the mating ritual, it all feels wonderfully gracious. You can order from the regular menu, as well as a special brunch list with first-rate omelets and creditable blintzes. (But beware the aforementioned feta pie and the astonishingly heavy potato floddies.) More choices: a special brunch buffet with jewels like fresh marinated mushrooms, smoked whitefish salad, herring in cream sauce, and, in a nicely ecumenical touch, separate-but-equal baskets of delectable croissants, bagels and blueberry muffins. There is even a sprinkling of babies and oldsters at brunch, and the soothing buzz of ordinary dining conversation. In the background, a good jazz pianist plies his trade, and in between, an occasional vintage Sinatra record caresses the ears. Ah, Cole Porter! Ah, civilization!