At Phoenix Ranch Market's new sit-down Mexican restaurant, there's always music. Sometimes it's piped in, but more often, it's performed by live musicians ? perhaps a band out on the courtyard stage, or a soloist singing romantic melodies from his vantage point behind a keyboard in the busy dining room. The spirited sounds make the festive atmosphere even more fun, and when Mariachi o Trio Alegria is working the crowd, it's an extra special treat to be serenaded at lunchtime. We're accustomed to seeing mariachis after dark, but these gentlemen were tableside on a recent Friday afternoon. Decked out in sharp traditional costumes, these three talented, smiling gents (two guitarists and a harpist) stroll from table to table, taking requests, singing triumphant folk songs, and causing outbreaks of applause at every stop. We're not sure if their performances actually enhance our appetite, or whether they just go well with frosty margaritas. Either way, "La Cucaracha" never sounded so good.