This recipe can be made into an adult cocktail by adding a little vodka.
½ cup white sugar
½ cup of water
4 cups cubed watermelon
3 cups cold water
½ cup fresh lemon juice
6 cups of ice cubes
Place the watermelon into a blender. Cover, and puree until smooth. Strain through a fine-mesh sieve.
Bring sugar and 1/2 cup water to a boil in a saucepan over medium-high heat until sugar dissolves, about 5 minutes. Remove from heat. Stir in 3 cups of cold water and the lemon juice.
Divide the ice into 12 glasses, and scoop 2 to 3 tablespoons of watermelon puree over the ice, then top with the lemonade.
Gently stir before serving.