RIO GRANDE CAFE -- 4919 Fairmont Ave., Bethesda. 656-2981. Open: Monday through Thursday 11:30 a.m. to 10:30 p.m., Friday 11:30 a.m. to 11:30 p.m., Saturday noon to 11:30 p.m., Sunday noon to 10:30 p.m. AE, MC, V. No reservations accepted. Separate non-smoking section. Prices: appetizers $1.95 to $6.95, entrees $5.50 to $11.95. Full lunch or dinner with drinks, tax and tip about $15 to $20 per person.

Put your glitter slippers in storage and get out your cowboy boots. The Texas culinary rodeo has begun in Bethesda. And the first entry is Rio Grande Cafe, with Tila's to follow. The Dallas-based outfit (which actually got its start in Houston) has brought to our city a new style, a kind of Wild West version of the designer chaos we first saw at Cities in Adams-Morgan.

The floor of the vast bare space that makes up the restaurant is concrete -- not just plain concrete, but intentionally scarred and stained concrete, kind of faux dirt. In the entry and along the walls are stacks of beer cartons and bags of rice -- not because they haven't been moved to a storeroom yet, but because they are design elements. The walls are painted like billboards for tequila and Corona beer, and in the center of one of the two dining rooms is a stainless-steel contraption about the size of a small elephant: a tortilla machine. If it weren't for the glass-brick walls and neon stripes, you might mistake the Rio Grande Cafe for a warehouse with tables.

But they don't serve such good tortilla chips in warehouses. Rio Grande's are thin, fresh and crisp, just lightly salted. With them is a salsa of near-pure'ed tomatoes, peppers, onions and cilantro, and it, too, is a citified version -- too tame for the Wild West.

This is not just an everyday Tex-Mex restaurant, it is haut Tex-Mex, with broiled quail and frog legs among the tacos and enchiladas. It is also our first big-time fajitas restaurant, serving skirt steak and chicken marinated and grilled over mesquite, accompanied by soft, warm flour tortillas and mounds of guacamole and pico de gallo -- a rather mild diced-tomato relish.

To start, there are margaritas served in beer mugs (or, of course, Mexican beer served in beer mugs). I keep hearing rumors of a wonderful drink that is a frozen margarita swirled with frozen sangria, but the sangria machine was broken on all my visits, and without a sangria machine, they apparently can't make sangria.

Appetizers are the predictable choices -- nachos, quesadillas or a casserole of melted cheese with fajitas meat or a pepper-mushroom-onion combination, and there are tamales, ceviche, tortilla soup and chile con queso. They are fresh, colorful, plentiful and mild -- and set the tone for dinner to come. This is no flame-throwing Tex-Mex restaurant, so fire-eaters might have to bring their own Tabasco.

The best of the main courses is the least likely entry on the menu. Broiled quail is sumptuously crisp and juicy, the butterflied and flattened little birds imbued with garlicky seasonings and mesquite smoke. They certainly don't need the melted butter dip that is served with them, nor do the mesquite-grilled shrimp, which are wrapped in bacon and stuffed with strips of hot green chile. The shrimp would compete with the quail except that their bacon wrap is left too raw.

Mesquite grilling is the kitchen's strength. Almost as good as the quail are costillas -- small, meaty pork ribs rubbed with sweet/hot spices and infused with the smoke from their grilling. And the fajitas, both beef and chicken, are also good food reminiscent of a campfire. The marinated grilled meat strips used in fajitas can be ordered on their own as a whole steak or chicken breast. Or they can be served already wrapped in a flour tortilla as tacos al carbon. The "crisp tacos," which are indeed crisp and very light, are not as delicious because their minced-meat fillings can't match the mesquite-grilled fajita meats.

Along more ordinary Tex-Mex lines, the enchiladas are made with high-quality tortillas that taste of corn, but their fillings -- like those for the crisp tacos -- are salty, bland and indifferent. Their sauce is just a neutral red or green moistener. Tamales are too dry and grainy, and their filling is minimal as well as minimally seasoned; but they are much improved by the cumin-dense chile that serves as their sauce.

If all this sounds too bland, chile rellenos is your dish. The chile itself -- embedded in a thick, light, eggy batter -- has been incendiary, but it is accompanied by the same vapid sauce as the enchiladas.

Nearly everything comes served with enough guacamole and pico de gallo to fill a six-foot taco. The guacamole certainly walks on the mild side, but it is rough-textured and refreshing. The pico de gallo is like a mild tomato salad. The platters also keep company with some nondescript beige rice and a soupy bowl of very good beans -- not refried, as Tex-Mex restaurants usually serve them around here, but freshly cooked with shreds of meat.

These are big batches of likable food. And it is served by likable kids who are spilling over with spirit but need a lot of seasoning. The waiters have alternately overwhelmed and underwhelmed us with attention. Pleasant as the waiters are, youthful charm doesn't substitute for actually bringing your food in order. At one meal, our main courses were brought while we were in the middle of our appetizers, and the rice and beans didn't come until we'd finished our main dishes. Once, when our table was overflowing with dishes and there was no room for the tortillas, we put them on the next table, ours being one of only two tables occupied in the whole dining room. The waiter panicked. That wasn't his station, he insisted, so we couldn't put anything on that table.

What's more, when we needed napkins, we had to find them ourselves on adjacent tables. Then busboys kept us busy grabbing our plates as they tried to clear them while we were still eating. And speaking of plates, we could get nothing but tiny appetizer-size plates when we wanted to share our main dishes. In all, the service was friendly but clumsy. I began to yearn for even a little surly efficiency.

Time may blunt those edges. In the meantime, Rio Grande Cafe is fun, with food that tastes more home-style than most Texas imports have offered before. ::