Gin, lemonade, ice, and either basil or mint (or both).
Don't just drop the herbs on top -- you can either put them in when you make the lemonade the night before, and let them infuse, or muddle them in the botom of your pitcher with a little lemonade before you add the rest of the lemonade, gin, and ice.)
It's kind of like a mojito, but lighter and lemonade-y. You can drink more of it before you pass out.
I just made that up, by the way. But I bet it would be good. I'm going to try it this weekend.