1. If you have time, pour the Hawaiian punch into ice cube bags or an ice cube tray and freeze.
2. Blend the blueberries in your food processor with the S blade. Add lemon juice and blend again. Transfer to a four-quart pitcher.
3. Pour in the ginger ale and cranberry juice. Chill.
4. Immediately before serving, pop the Hawaiian punch cubes into the pitcher (or, if you didn’t make cubes, just pour in). Add wine, if desired. Float lemon slices on top.