1 oz of Cranberry Juice
1 oz of absolut ruby red vodka (or Smirnoff Raspberry Twist Vodka)
4 oz of squirt citrus soda (or orange soda)
Simple cocktail method, fill the glass full with ice, pour desired amount of Absolut Ruby Red Vodka, add Squirt, leave some space for cranberry juice.\r
Substitutions could include: unflavored vodka instead of Ruby Red(however not as grapefruity) or Grafs 50/50 pop instead of Squirt. The key is to have grapefruit pop. I have not yet tried grapefruit juice, but suspect the absense of carbonation would make the drink suffer.