A Pisco Sour is a classic cocktail brought to states via Chile and Peru. It contains of Pisco (a Peruvian grape brandy), lemon and lime juices, simple syrup and raw egg whites. No need to be grossed out by raw egg whites either — I've found that, when served in a cocktail like this, they turn light and frothy and give the drink a smooth texture, very similar to that of an Orange Julius drink (minus the icy bits).
I've found this handy dandy online video tutorial (below) in case you feel like whipping up a few of your own at home. For the Pisco, you'll be able to find it at a large liquor store (like a ABC or Total Wine) and as for the raw eggs — consume at your own risk. Your best bet is buying them from a local, reputable farm that doesn't use hormones or antibiotics in their chickens.
Image via Tierra Unica.