Thread 3 frozen cherries onto each skewer. Put in the freezer until ready to garnish the drinks.
Pour 2 tablespoons of grapefruit juice into each of 4 champagne flutes and top with the 1/4 cup of sparkling grape juice. Add 1/2 tablespoon of the reserved cherry sauce and garnish with the frozen cherry skewers.
For the adults, add 1-ounce of Amaretto liqueur.