Remove the pulp from a large watermelon. Puree in a blender and strain to remove any large seeds or particles. In a two-gallon jug, combine the puree with the juice of 4 large limes. Add lime rinds. Add one-third cup of granulated sugar and 6 cups of water. Adjust flavor adding more sugar, water or lime juice as needed. Serve over ice and garnish with lime wedges.
For extra kick, combine with rum. Also add to freshly brewed ice tea and garnish with mint for extra refreshment.