In a blender, combine bananas, sugar and 3 cups water. Blend until smooth. Pour into a large bowl and stir in pineapple juice. Blend in orange juice concentrate, lemonade concentrate and 3 cups water. Divide into 3 plastic containers and freeze until solid.
Remove from freezer 3 to 4 hours before serving. Using one portion at a time, place slush in a punch bowl and pour in 1 liter of ginger ale for each.
