Forget the Big Gulp, 7-Eleven's Double Gulp is a 64-ounce (almost 2 liters!) answer to summer's oppressive heat. But chugging this mobile storage tank will add about 600 calories to your day (even more if you opt for a Double Gulp 1,200-calorie Dr. Pepper Slurpee). On the other hand, watch us do the happy dance if we find one of the few 7-Eleven swirling frozen concoctions we can absolutely love: a Crystal Light Peach Mango Fusion Slurpee with just 60 calories per 12 ounces. Summer, here we come!