Prepare the simple syrup by combining 1 cup of sugar with 1 cup of water in a small saucepan. Heat on medium, stirring until the sugar completely dissolves. Remove from heat and let cool completely.
Juice the fresh citrus if using. For maximum juice yield, roll the fruits firmly on the counter before cutting and juicing them. Strain out any seeds and pulp if desired.
Combine all juices in a large punch bowl or pitcher, stirring gently to mix the pineapple, orange, cranberry, lemon, and lime juices together with the cooled simple syrup.
Refrigerate the juice mixture for at least 2 hours to allow the flavors to meld and develop. This step is crucial for achieving the perfect flavor balance.
Just before serving, add the carbonated beverage (ginger ale or lemon-lime soda) to the juice mixture. Pour slowly down the side of the bowl to preserve as much carbonation as possible.
Garnish your punch by adding the sliced citrus fruits, fresh berries, and optional mint sprigs to float on top. For an extra special presentation, freeze some of the fruit slices or berries in ice cubes beforehand.
Serve immediately in glasses filled with ice, ensuring each glass gets some of the floating fruit garnishes.