When I was in Rio for business, one of my hosts took me to lunch and we had Caipirinhas, but with vodka instead of cachaça. He explained it would make it harder to detect on your breath. Either way, they're very sweet and go down nicely.

A caipirinha with vodka is called a caipiroska. I name my computers after caipirinha varieties. Once at the office my laptop screensaver was showing "caipiroska" and a Russian guy exclaimed, "what's that?!?" Apparently "piroska" has a certain connotation in Russian that's nsfw.