The mint julep is a mixed drink originating from the South in the United States. It is essentially a smooth, sweetened, slightly minty bourbon drink. From personal experience, you cannot find this drink (or anyone competent to make it) in the North. However, I would believe it to be a capital offense for a Southern Bartender to be incapable of making one.

Recipe Ingredients:
6 fresh mint sprigs
1 tsp sugar
2 tsp water
3 oz. Bourbon (I have seen a variation with brandy but I suspect it to be Unamerican)
crushed ice

Crush 4 of the mint sprigs and muddle with the sugar and water. Add Bourbon and enough crushed ice to fill the glass. Garnish with the remaining mint sprigs, ideally placing them such that your nose smells the mint as you sip. Supposedly it is best through a grass straw, but I cannot speak to this from experience.

Once, a bartender above the Mason-Dixon line was willing to try to make one for me. I figured I was safe since I was in a Thai restaurant and therefore could count on them having fresh mint. It seemed to take an eternity to arrive, but I was occupied with some Tom Kar soup. At one point I looked over towards the bar and saw the bartender scooping after-dinner mints. I was worried, but thought he might just have another bowl of them on the bar. I was wrong -- he had mashed them up and put them in. Instead of a lightly minty sweetness softening the bourbon, it resembled a cough drop.

Moral: If a bartender doesn't know what a drink is off the top of their head, don't let them make it, especially if it's more complex than mixing liquids and ice.