Mix grapefruit juice and simple syrup in champagne flute. Top off with champagne. Makes 1 serving. Tip: To make simple syrup, heat 1 cup sugar and 3/4 cup water in small saucepan over medium heat just until the sugar is dissolved. Chill before using. This makes about 1 1/4 cups simple syrup. Store in covered glass jar in refrigerator. Tip: For variety, you can substitute raspberry or strawberry syrup for the simple syrup.