Here are a couple of possibilities:
1. Wine punch:
- bottle dry white wine
- muddled basil & mint
- sliced peaches
- splash of grand marnier
- vodka to taste
2. Drinks bar (this suggestion borrowed from the NYTimes). Set out the following for your guests:
- simple syrup
- seltzer
- sliced fruit & berries
- pureed fruit (peaches, pineapple)
- mint & basil
- lemonade or limeade
- ginger ale
- selection of liquor: vodka, rum, tequila
Let them mix up combinations for themselves!
3. Kir Royale (& variations)
in individual flutes, combine:
- 4 parts sparkling wine or champagne
- 1 part crème de cassis
- berries, fruit
or, in a punch bowl:
- dry white wine
- crème de cassis
- sliced fruit