Curve Street Sour

A variation of the classic Whiskey Sours, named for the Alley's previous identity as the Curve Street Extension.
This classic cocktail dates back to the late 1870's, created by a bartender in Chicago, who claims to have created the Manhattan.
Even though the Manhattan part can't be proven, it seems the Whiskey Sour has been found to be true.  Originally the Continental Sour, then the Southern Whiskey Sour, it became popularized as the New York Sour.