Step 1: Prepare simple syrup: In a small saucepan, combine 2 cups granulated sugar and 2 cups filtered water. Heat over medium heat, stirring until sugar is completely dissolved. Do not boil. Remove from heat and let cool completely. This can be made several days in advance and stored in the refrigerator.
Step 2: Juice lemons: Roll fresh lemons on a countertop to maximize juice extraction, then cut in half and juice them until you have approximately 1.5 cups of fresh lemon juice. Strain to remove pulp and seeds.
Step 3: Make classic lemonade base: In a large pitcher or drink dispenser, combine the cooled simple syrup, 1.5 cups fresh lemon juice, and 4 cups filtered water. Stir well. Taste and adjust for desired sweetness or tartness. Refrigerate for at least 1 hour to chill.
Step 4: Prepare berry puree: In a blender, combine 1 cup of fresh or frozen berries with 2 tablespoons of water or simple syrup. Blend until smooth. For a smoother puree, strain through a fine-mesh sieve. Transfer to a small serving bowl or jar.
Step 5: Prepare peach puree: Peel and pit 2 ripe peaches. Blend with 1/4 cup of water or simple syrup until smooth. Transfer to a small serving bowl or jar.
Step 6: Slice garnishes: Thinly slice the cucumber. Wash and separate fresh mint sprigs and any other desired herbs. Slice extra lemons, limes, and oranges for additional garnishes. Arrange these in small, separate bowls.
Step 7: Set up your lemonade bar: Arrange your lemonade base dispenser, purees, sliced fruits, fresh herbs, and plenty of ice on a clean table. Provide glasses, stirrers, and optional sparkling water.
Step 8: Instruct guests to pour a base of classic lemonade, then add their desired amount of purees, and finish with fresh fruit and herb garnishes.