A big sporting event that's about as Mexican as you can get happens here February 16 - 20, the popular charreada as much an elegant custom steeped in history and tradition as a rodeo. The costumes are part of its dramatic beauty, little changed from those worn in the 19th century. Both the cowgirls and cowboys wear sombreros, the men very dapper and the women in long skirts trimmed with sequins, embroidered white shirts, and colorful rebozos draped over their shoulders. Sitting sidesaddle they're much more than a decoration, however, performing astounding feats like bringing their galloping horses to a screeching stop. Accompanied by mariachi music, the competition's 18 'games' demonstrate in grand style a real pride in the skills traditionally learned on ranches here, like cattle roping. And the fun's not over once the winners have been announced, because that's when the eating, drinking and dancing begins.