Like most of Seattle's Mexican restaurants, Guaymas Cantina serves standard Tex-Mex fare, and its patrons tend to be office drones who come for the sake of convenience. But so far as finding a good downtown happy hour goes, perched high above the Harbor Steps, it's one of your best bets. Twice daily, Guaymas offers $5 margaritas, $4 wells, and $3 beers. (If you really want to get down to business, ask nicely, and your server may give you a chilled silver tequila shot in lieu of a margarita.) Better still, the restaurant is relatively empty after the lunch rush, which translates to drinks delivered at lightening speed, along with bottomless baskets of free (!) chips and salsa. The only place you'll enjoy a better priced fiesta is, well, Mexico. ERIKA HOBART