Make the ice mold: Arrange the grapes in a bundt pan. Slowly pour in water halfway up the grapes. Tuck the bay leaves around the grapes so they’re partially submerged. Cover with plastic wrap and freeze for 6 hours, or up to 24 hours.
Make the bowl: In a large punch bowl, combine the red wine, lemon-lime soda, lemon juice, and lime juice. Stir to combine, then cover with plastic wrap and refrigerate for at least 1 hour, or up to 4 hours.
When ready to serve, remove the bowl from the refrigerator. Hold the bundt pan upside down in one hand and run the bottom under hot water until the ice mold drops into your hand. Float the ice mold in the bowl (with the grapes facing up) and serve.