It all began here in 1993: salsa classes on Monday and Wednesday nights at the spacious and charmingly down-at-the-heels Blue Banquet Hall. By now the place is packed four nights a week, and Salsa Lovers is a huge enterprise, having expanded to two more locations. But the West Miami-Dade scene has a festive, nightclubby quality all its own, and it just keeps getting hotter (sometimes literally; the AC is erratic). Monday through Thursday a large and varied crowd descends on the hall, everyone from senior citizens to families to middle-school students, though the 20- to 30-year-old crowd dominates. The sheer energy generated by hundreds of slaves to the salsa rhythm is irresistible. Some people skip the classes and instead hang out, flirt, or practice moves with a partner. Between classes (three levels, each one hour long, beginning at 7:00 p.m.) the DJ spins a "practice song," and a gigantic circle of couples fills the entire main dance floor, so big the instructors have to call out the turns on a microphone. Oscar D'Leon blares from the speakers, and pretty soon everyone's in a whirl -- dile que no, dame una, hips going and fondillos shaking, abrázala, abanico, arms rising and feet pivoting, monta?a, balsero, and sometimes the lights will dim and the tacky disco balls will turn. For seven dollars (price per lesson) you get all this, and you might even learn the paseo por el parque.