Irma's has been a Houston institution for years, holding court in a cramped but festive building almost directly underneath 59 South. The crowd is full of regulars, who know not to ask for menus (a list of available items will be delivered orally). This is the place to fill up on the fine frozen margaritas, fresh lemonade and crisp, salty chips dipped into fantastic guacamole. It's depressing how often guacamole in this town is presented at baby-food consistency, betraying a prepackaged pea-green color and all but flavorless. Not so at Irma's, where chunks of ripe avocado stand out for texture, garlic flavor is prominent and fresh cilantro and minced jalapeño garnish a bowl of guacamole done right.