TUESDAY USED to be the Maytag repairman of nights out. Back when weekends were weekends -- when the calendar was divided between the worknights and FridayandSaturday -- Tuesday was smack in the middle of the slough of despond, halfway between last call Saturday night and dawn of hope Friday morning. And now that ABC has invented a rowdy-rounds tradition for Monday night football, Tuesday is even lonelier, so bedraggled that Maryland has had to create a Lotto drawing to keep it in business.

Well, things have changed out in Annandale, where thanks to the hybridized New Orleans, R&B, rockabilly, bordello blues, pickup brass and sometime marching band The Red-Hot Swinging Johnsons, every Tuesday is Fat Tuesday at the Sunset Grille.

Get a clue -- we're talking Professor Longhair with a bow-and-saw in the roadhouse. The Sunset Grille, which is about the size of a small goat corral (and attracts patrons with elbows sharp as horns), is the sort of hangover hangout that, going nose to nose with a Fuddruckers, reminds you that there are still embattled enclaves of Northern Virginia resisting the yuppie invasion like modern-day Mosby's Raiders.

In fact, if the Sunset Grille is "the inland beach bar," as it advertises, it can only be talking about China Beach; because the early-shift regulars, the heavy 4-to-8 o'clock crowd (the ones who get phone calls from home), are as likely to be wearing camouflage or Vietnam vet memorabilia as trucking or agribusiness caps. And as to gunpowder, committed nonsmokers even of the passive variety should probably come equipped with oxygen masks, since the Sunset Grille's ventilation system is fighting a losing battle -- one against the world. (The Grille hasn't even bothered with a cigarette machine; the bartender still dispenses packs from an open case on the wall.)

But it's a great place, all the same: beer and mugs right out of a glass-door cooler, cheap steaks, fat spaghetti, daily dinner specials -- the sort of kitchen that serves garlic toast with every entree. In the finger-food vein, there are quesadillas, nachos, buffalo wings, plus a half-dozen kinds of shrimp baskets, including a version called "Bud style" that ought to become a local standard: peeled shrimp boiled in beer and seasoned with Old Bay.

There are few strictures here. Sit down at the bar and prepare to be introduced to at least the three people closest by. If you are solitary, they may offer to buy you a beer; even if you're not alone, you may find yourself dancing (in two square feet) with any number of unknown partners.

Which brings us to the second shift of patrons -- about 20 to 45, ranging from women with frizzy permanents and kohl-black eyes to quartets of Hispanic youths to Elvis survivors and R&B babies, who begin squeezing in after the happy-hour freebies elsewhere. Which also brings us to the aforementioned Swinging Johnsons (not to be confused with the "Incredible Johnsons," a k a The Amazing Johnsons, also an R&B group), who have the same family relationship as the Ramones or the Wilburys.

According to John Combs, the somewhat inadvertent founder of the group, it began early this year as an amalgam of moonlighting and temporarily unattached musicians, inspired when Combs wandered into the Sunset Grille on a Tuesday while a single guy on acoustic guitar was entertaining a minimal crowd -- Combs and one other person. Combs suggested to the manager that he throw a band in on Tuesdays and see if they couldn't work up an audience, and within a couple of months it had evolved from a lark to a living (more or less). Now the Johnsons play the Sunset Grille every Sunday and Tuesday, and the Falls Church Champions on Friday, as well as whatever other gigs the various musicians have.

Combs, for instance, who plays stand-up and electric bass and keyboards, also plays with Doc Scantlin's Imperial Palms Orchestra, and had 10 gigs in a week recently, which explains his half-closed eyes some nights. Other relatively regular Johnsons include Ted "Too-Tall" Watkin on sax and saw; ex-Tex Rubinowitz drummer Jeff Lovson; sometime Billy Hancock and Evan Johns guitarist Tommy Gross and Grandsons of the Pioneers/Little Red saxophonist Chris Watling. Some nights it's a three-sax section: Joe Stanley, a Cagney-as-Cohan lookalike who's been playing sax on the Elks Club circuit, has come in for Derek Houston, who has moved to the source, New Orleans. (Sleazy/greasy kool keyboardist Ivan Brown is in the process of moving to Texas, so those with fond memories of the old H-Bombs better look in fast.)

We are talking rowdy, here; and when they get going, the Johnsons may start a Nawlins-style sidewalk strut parade or even jump up onto the bar. And since the Sunset Grille genteelly eschews cover charges, the Johnsons employ a beer pitcher for a "tip jar," so come prepared to show your appreciation in a material fashion.

The Sunset Grille (703/658-0928) is on Columbia Pike just a few doors off Little River Turnpike; if you're coming west on Little River from the Beltway, for instance, you'll have to make a triangular detour, turning left onto John Marr Drive at the K mart and left again onto Columbia Pike.

Incidentally, some musical miscreant stole Combs's upright bass from his car in Dupont Circle a few weeks ago -- not the sort of thing you would have thought somebody could just tuck under their arm. Anybody whose neighbor has suddenly acquired a rather large objet, or anyone with a Santa Claus complex, please drop Combs a note, c/o the Grille.

HARMONY & UNITY: The return of 10-year Prairie Home Companions Robin and Linda Williams is good news in itself, but their concert Saturday at the Silver Spring Unitarian Church may be a harbinger of even better days for folk music lovers. The Williamses' appearance marks the first joint production by three of the area's most generous and reliable showcasers of acoustic music: the Folkal Point of Ellicott City, the Weathervane of Frederick and the House of Musical Traditions in Takoma Park. Appearing with the Williamses are Jim Watson (vocals and bass) and Kevin Maul (dobro). Admission to the 8:30 show is $10 at the door; for more information call 301/982-0686 or, from Baltimore, 301/381-2460.