Watermelon Cosmopolitan

"I know…the end of summer is drawing near. But let's make the most of it with this cocktail. You grab the fruit and ask friends bring the alcohol. I'll bring the blender."—David

Tip: Want to make a party-sized portion of this drink? Use a regular-sized seedless watermelon, increase the remaining ingredients, and use the watermelon rind as a serving bowl. Toss when empty. Easy!