Enjoy this even fruitier version of a classic Shirley Temple for Halloween. Just combine grenadine, grapefruit soda, and white rum in a cocktail shaker, pour into a martini glass, and garnish with what else but a maraschino cherry.
Combine rum, grenadine, and 1/4 cup soda in a cocktail shaker with ice. Shake until cold. Strain into a martini glass and top with remaining 2 tablespoons soda. Garnish with cherry.