Pisco sours have won my heart, and I think they will win yours too. In fact, if you haven't permanently traded in margaritas for pisco sours by Monday, I'll give you your money back.
This family recipe for this traditional Peruvian drink I snatched from a Lonely Planet guidebook on Peru. Try it out:
3 parts pisco (a Peruvian rum-like liquor made from grapes, see "Pisco is Peruvian, carajo!")
1 part freshly squeezed lime juice
1/3 egg white
1 part sugar (or Cane syrup)
Combine the lime juice and pisco in a blender. Add sugar to taste. Add plenty of ice and blend. Spoon in egg white and blend again. Serve immediately. Add a drop of bitters to the top for decoration.