Rum Punch with Melon Balls

Make melon balls (about 3/4 inch each) using a melon baller. (You should have about 2 cups.) Transfer to a rimmed baking sheet, and freeze, about 1 hour.

Stir together pineapple juice, rum, lime juice, and bitters in a punch bowl. Slowly add ginger ale, being careful not to disperse the bubbles too much. Add frozen melon balls. Serve immediately.