1 small can (6 ounces) frozen orange juice concentrate
1/4 cup lemon juice
Combine all ingredients in a large jar or pitcher and chill.
To make watermelon juice, process small chunks of watermelon, with seeds removed, in a blender or food processor until they turn to liquid. Make more than you need for this punch, freeze the extra in ice-cube trays, and use the watermelon cubes to chill the punch. (You can also use watermelon juice instead of water when preparing frozen lemonade or limeade.)