Puree all ingredients in a blender. (You will have to make the drink in 2 batches so as not to overflow blender.) Serve in champagne glasses. The drink can sit a while before serving, but re-blend it to "froth it up". Garnish glass with a spring of mint or line slice.
You can substitute strawberry yogurt and fresh or frozen strawberries.
You can cut this recipe in half for a smaller amount of servings. Save half can grape juice in freezer for next time.