Tahitian Punch
["1 (46 oz.) can pineapple juice, chilled", "1 (46 oz.) can orange-grapefruit juice, chilled", "1 (2 litre) lemon-lime drink, chilled", "1 pt. lemon or lime sherbet"]
["In large punch bowl, stir together juices, and add lemon-lime drink.", "Using", "an ice cream scoop or spoon, float sherbet on top. Serve immediately."]
["pineapple juice", "orange-grapefruit juice", "lemon-lime drink", "lemon"]