Ingredients: 8 large sprigs of fresh mint, 4 cups cubed seedless watermelon (3/4-inch cubes are perfect here), 1/2 cup simple syrup, Ice cubes (you'll need about 2 quarts), 2 cups white rum (I like D'Aristi rum from Yucatan), 1/2 cup fresh lime juice, Sparkling water or club soda
Directions: Set out eight tall 12-ounce glasses. Put the leaves stripped off a single sprig of mint into each glass--you'll need about 10 leaves for each drink--and top with 1/2 cup watermelon cubes. Divide the Simple Syrup among the glasses (1 tablespoon - 1/2 fl. oz. per glass). Use a muddler (or the handle of a wooden spoon or a long-handled iced tea spoon, though neither is anywhere near as effective) to crush the mint and watermelon, releasing their flavor into the syrup--the more muddling, the fuller the flavors. Fill each glass with ice. Measure in the rum (1/4 cup - 2 fl. oz. per glass) and the lime juice (1 tablespoon - 1/2 fl. oz. per glass). Use a long-handled iced tea spoon to mix everything together. Top off each glass with a little sparkling water or soda and you're ready to serve.
Recipe courtesy of Fine Cooking.