The Triangle is a big, boisterous Italian restaurant and bar -- a place with all the requisite trappings of wood paneling and mussels marinara. What sets it apart is the house band. The performers are an exceedingly average-looking, post-middle-age troupe, performing a repertoire of old standbys and what can only be described as classic rock. Imagine, if you will, your Uncle Tommy, T-shirt, jeans and beer gut a-go-go, belting out a powerhouse version of "Born in the USA." Better yet, imagine him doing "Do Ya Think I'm Sexy?" Needless to say, it's not a pretty picture. But it is, I assure you, a compelling one. There is something both perverse and charming about the floor show at the Triangle -- something that big city neo-swank hot spots, with their martinis and their cigars and their relentless irony, could never hope to have. People go to the Triangle not to look good but to have a good time; and the guys in the band even have a perma-"having a ball" expression plastered to their faces. The patrons cheer wildly. And you come away with the feeling that if only Uncle Tommy did have a band, he'd be a much happier guy.