LAS MARGARITAS Downtown tends to be vacant and gray around 5 o’clock on an autumn evening. Then there’s Las Margaritas. Step inside this downtown Mexican restaurant from 3 to 7 p.m. any day of the week, and the word “dreary” will erase itself from your vocabulary. The colors are brilliantly south of the border, the game’s usually on TV, and the smell of warm tortilla chips pervades. Standbys like beef, chicken, or cheese quesadillas and supernachos are available for $5 during happy hour. Draft beers are poured for $2.50 (Bud and Bud Light) to $3 (Tecate, Dos Equis, and others) and frozen margaritas are $3.75. 1122 Post Ave., 206-623-7203. DOWNTOWN