How to Make It
Line a large baking sheet with wax paper. Holding each grape cluster by its stem, dip it in the beaten egg whites and sprinkle with sugar. Arrange the clusters, without touching, on the baking sheet and freeze until solid (or for up to 1 week).
In a large bowl, combine all of the ingredients and mix very well. Refrigerate overnight.
Pour the punch into a chilled punch bowl. Add the ice block and scatter the sliced fruit on top. Hang the sugared grapes around the edge of the bowl. Serve the punch in cups with a splash of seltzer and a cluster of grapes in each cup.