Combine all ingredients in a medium bowl; stir until sugar melts. Pour mixture into 9x13" baking dish; place in freezer for 1 hr. Remove dish from freezer; use a fork to scrape up any ice crystals. Return dish to freezer and repeat scraping process every 15 min. for approximately 3 1/2 hours. When mixture is thoroughly frozen, fluff with a fork and freeze another half hour before serving in a dessert dish with a spoon.