"Awesome. Terribly awesome," says bartender Eddie Donelan of his weekend nights tending bar at one of D.C.'s hottest rendezvous spots, Pierce Street Annex.

At this singles bar there's often barely enough elbow room to write a few phone numbers when young professionals make contact, particularly on Friday and Saturday nights when the clientele swells way beyond the club's 412- person capacity. And outside you'll find an additional 200 potential prospects sweating and straining toward another bar. Bartenders estimate that they go through 10 half-kegs of beer on a Saturday night -- that's 150 gallons, or 1,600 12-ounce glasses.

The Annex's customers are not the shy or self-conscious type; even the matchbooks strongly suggest that you meet and greet fellow patrons. On the outside of the bright orange cover is the command, "Have a drink before striking." Inside is a short form for name, address and phone number and the slogan, "Aside from the best in music -- a very 'mellow' sociable scene."

Other touches of that sort include metal copies of old trademark signs reading "Lay or Bust Poultry Feeds" and "Finck's 'Detroit Special' Overalls, Wear Like a Pig's Nose." And by the way, the sign that reads "Woofers" marks the men's room door; "Tweeters" is for the ladies.

"Sure we have a meat-market reputation," says Patience ("Shuntz" for short), a bartender from Manhattan. "But most bars in D.C. are like that."

Manager Jimmie Reed says his saloon may be the biggest in Washington, but "we're very much a singles bar -- not a meat market. If a girl wants to get picked up, she can get picked up. But it's the same thing out on the sidewalk."

About 90 percent of Reed's patrons are professionals between the ages of 21 and 45. "We have IBM executives come in here, lawyers and secretaries. We don't hide the fact we're a singles bar," Reed says. "But really any bar or saloon short of the YMCA should be considered a singles bar. There's no such thing as a married bar."

Bartender Donelan describes the clientele as "nice girls and easy-going guys. Mainly good-looking people."

Disc jockeys from Nard's Rock and Roll Revue spin the tunes nightly; occasionally, there's a live band. The wooden dance floor offers room to bump and swing and the gazebos and scattered tables and chairs give comfort to tired feet.

Pierce Street Annex sponsors a happy hour Monday through Friday from 5 to 8:30 p.m. with free hors d'oeuvres such as tacos, barbecued spare ribs, veggie and cheese trays and $1-off ladies' drinks. The mixed drinks cost $2.25, call-liquor mixed drinks run $2.75, domestic draft beer is $1.75, draft Heineken is $2. Every Monday night at 8:30 there's a backgammon tournament with cash prizes.

If you get hungry, the Sichuan Annex is right next door serving Chinese food until 10:30 p.m. during the week, 11:30 on weekends. The restaurant has direct access to Pierce Street's dance floor but Reed says he has an agreement with the Sichuan owners that they won't serve food in his bar.

You have to be 21 to get into Pierce Street Annex. However, doorman Omar Fakhoury is quick to point out other bars that will serve you if you're not old enough to get in his place. And there's a dress code.

"Guys must have collared shirts and no tattered jeans or torn sneakers. But shorts are allowed," says Fakhoury.

Mike, an IBM engineer who declined to give his age or last name, comes to Pierce Street because "It's a friendly crowd. It's one of the few bars in town where the people who work here are allowed to talk to the customers." PIERCE STREET ANNEX -- 1210 19th Street NW, 466-4040. Open until 2 Monday through Thursday, 3 Friday and Saturday. No cover or minimum.