2/3 c. sugar
2/3 c. water
1 c. grapefruit juice
1/2 c. orange juice
3 tbsp. Grenadine
1 bottle ginger ale, chilled

Stir sugar and water over low heat to dissolve. Bring to a boil and boil 10 minutes. Cool. Add sugar mixture to orange and grapefruit juices. Chill. Just before serving add grenadine and ginger ale.