Combine grapefruit juice drink, butter, brown sugar, honey and red pepper flakes in a medium saucepan. Cook over medium heat, stirring until smooth, 4-6 minutes. Set aside to cool 10 minutes. Arrange chicken breasts in a 11x7x1-1/2-inch baking pan. Pour 2/3 cup marinade over chicken just to cover, reserving 1/2 cup. Cover pan with plastic wrap. Refrigerate and marinate for 30 minutes. Remove and turn chicken over, allow to marinate another 30 minutes. Divide remaining 1/2 cup marinade in half again; 1/4 cup will be used for basting and 1/4 cup will be used for serving. Preheat grill. Grill chicken for approximately 4 minutes on each side; basting once or twice per side. Cook until chicken reaches 170° F on an instant-read thermometer. Warm remaining 1/4 cup marinade, drizzle over chicken. Makes 4 servings. Per Serving (with Ocean Spray® Ruby Red Grapefruit Juice Drink): Cal. 349 (17% DV), Fat Cal. 117, Pro. 26.4 g (53% DV), Carb. 39.1 g (11% DV), Fat 13.0 g (20% DV), Chol. 96.2 mg (320% DV), Sod. 159 mg (7% DV), Vit. A 104 RE (13% DV), Vit C 11.7 mg (20% DV), Vit. E 0.4 mg (2% DV), Calcium 32 mg (3% DV), Iron 1 mg (7% DV), Folate 4.2 Ug (1% DV), Zinc 1 mg (7% DV), Pot. 322 mg (9% DV), Dietary Exchange: Fruit: 2 Meat: 3 Fat  1.5