Sparkling Sunshine Punch

Makes about 16 servings.
Ingredients
half gallon white grape juice, chilled
12 red seedless grapes
1 bottle (750 ml) sparkling red grape juice cocktail, chilled
1 liter lemon-flavored mineral water or seltzer, chilled
Directions
Pour two cups of the grape juice into a pitcher. Fill the compartments of a 12-portion mini-muffin tin 3/4 of the way full and place in the freezer until frozen, about two hours. Meanwhile, cut each grape lengthwise into 8 even wedges. When the juice in the muffin tin has frozen, arrange one grape in a concentric circle, overlapping slightly, in each compartment, resembling a flower. Very slowly fill each muffin cup to the rim with more grape juice without disturbing the pattern. Freeze until firm. Make several batches of the blossoming grape ice cubes and refresh them as they melt in the punch.
To make the punch, fill a large punch bowl with the white grape juice, then add the sparkling red grape juice and lemon seltzer. Remove the muffin tin from the freezer and let stand five minutes for the cubes to release from the pan. Carefully remove the frozen grape "flowers" from the muffin tin with a small spatula and float them in the punch. Serve immediately.