AGUA DE SANDÍA (WATERMELON PUNCH)

This summery Mexican beverage, which Niloufer Ichaporia King mixed up for the early hours of the Bolinas potluck, can be turned into a refreshing cocktail with the addition of cachaça or white rum to taste. Seed an 8-10-lb. watermelon (preferably yellow), then purée the pulp in a blender or food processor. Strain into a large wide-mouth jar to catch stray seeds. Squeeze 3-5 quartered limes into jar, adding the rinds. Add 1/4 - 1/2 cup granulated sugar and 6-8 cups water and mix well. Adjust flavor with more sugar or limes, if you like. Add plenty of ice, then ladle into tall glasses. Makes 1 gallon.