The cuba libre, rum and Coke, always seemed like a pop cocktail to me. I guess I associated it with early drinking in college, when it was the only mixed drink anyone knew how to make and seemed like a painless way to ingest a lot of alcohol.
But that was before I tried Ernest Hemingway's recipe for a cuba libre, which is something else again. The key to this recipe is getting hold of a Mexican Coke, which is still made with sugar, as it was in Hemingway's day. You want to taste the rum and its parent cane sugar all at once. (If you can't find Mexican Coke, forget I ever mentioned the cuba libre -- corn syrup has no place in it.)
Squeeze half a lime into a cocktail glass. Pour in a jigger of Bacardi white rum, add the remains of the squeezed lime and plenty of ice and pour the Coke over it. The result is not too sweet and not too sour and it has an exhilarating freshness. After a couple of these you'll be imagining you're on a tropical beach somewhere . . . and after a few more you'll be convinced you really are on a tropical beach somewhere.
At that point, just relax and listen to the sounds of the surf and the wind rustling the palm fronds.