1. Prepare ice ring: Fill 5-cup ring mold with 1/4 inch water; freeze until firm. Reserve 8 strawberries; slice remaining strawberries. On ice in ring mold, arrange one-half of sliced strawberries, 1/2 cup grapes, and enough water just to cover fruit (so fruit does not float).Freeze until firm. Repeat with remaining strawberry slices, another 1/2 cup grapes, and enough water to cover fruit; freeze until firm.
2. With kitchen shears, cut remaining grapes into small bunches; alternately arrange grape bunches and reserved whole strawberries in ring mold; tuck leaves here and there between grapes and strawberries. Add enough water to come up to rim of mold, allowing some fruit to extend above water; freeze until firm.
3. About 15 minutes before serving, in shallow 5-quart punch bowl, large enough to hold ice ring, combine orange juice, black-currant liqueur, and sugar. Gently stir in chilled club soda and champagne.