Open daily, 7 a.m. to 8 p.m., until midnight when

National Theater is open. No credit cards or reservations. Free delivery.

We all know about lunch, In fact, we all know too much about lunch, that daily break in routine that in itself becomes routine. The lunch break, the working day's big chance for adventure, is also the make it or break it time for a substantial proportion of downtown restaurant. Thus they, too, fall into routines, daring not to risks of losing the hamburger crowd or the chef salad diehards.

But downtown - Washington's old E and F street department store corridor from Hecht's to Garfinckel's - is making a lunchtime come back. Not only are there new restaurants, but new kinds of restaurant. Here are three that might even eat into the Reeves routine.

"What you see is what you get is one of the many mottoes of Frisco's. There is a lot to see. Frisco's hits you first with its sidewalk cafe, scomplete with waitress and an urban view of the Federal Triangle bus traffic. Inside is the real action, the cafeteria lineup of mix and match, call your order loud and clear lunches that makes you vow to memorize the menu and plan your order for next time.

Frisco's steadfastly maintains a cafeteria ambience despite the globe lamps and half timberish setting, the ceiling hung with rows of little pewter colored beer mugs. And its jack of all trades menu doen't really have one item of potential stardom. Rather, it is the array, the variety and the amount of food for the orice that packs them in.

First, there is the salad bar setup, with two sizes of paper plates, allowing all one can pile on a single plate - $1.05 for the small, $1.85 for the large. Right away the regulars stand the sout, having obviously practiced and given considerable thought to the method of piling the twenty or so items six inches high and maintaining the balance all the way to the cashier.

The next big draw is a bargain item called "1-2 sandwich specials, "the deal being that half a sandwich - barbecue, corned beef, roast beef, steak and cheese, chicken salad, club, ham and cheese and such - comes with a bowl of soup (homemade and quite respectable), coleslaw or potato salad (the potato salad is commendably eggy), and pudding (no worse than standard) for $1.45 to $1.40, the average being about $1.75. As for the sandwiches, the roast beef is rare, which means it is companion stated," tastes like homemade," which means it is probably made with commerically bottled sauce. None of the food is a knockout - the bread is Washington's usual flabby sliced rye and sandwich white - but it is all tasty, and the sandwiches are of impressive weight. Besides the sandwiches, there are daily specials such as pork chops, and fried chicken which sells at $1.25 the quarter. A foot-long hot dog is no bargain at $1.95, but it is a garlicky kosher style hot dog slashed and grilled and very good. And that's not all. Gyros, that enormous revolving Middle Eastern meat loaf, and baklava add a cosmopolitan air. There are even beer (sixty five to eight five cents for twelve ounces), wine (seventy five cents a glass) and pinball machines to round out the program. The finale - ice cream cones, in a staggering array of flavors. With all this, a friendly crew to serve (as long as you call your order loud and clear and answer quickly to the mayo or mustard queries).

Oh, yes, can even get a simple - whole - BLT. $1.50. Mayo?