The first, of course, is to slice, segment, and eat it for breakfast. Grapefruit is served "classic style" when it is eaten with a slice of toast and coffee. But if the work day is complete or you are otherwise enjoying a Sunday afternoon. and have a juicy grapefruit available, make a Greyhound!
It is a criminal waste of vodka to make a greyhound with canned or bottled grapefruit juice so I only enjoy this classic cocktail when I have a grapefruit on hand. Fill a highball to the rim with ice. Add 2 oz. vodka (or your preference) and then add the juice of one grapefruit (including just enough pulp to your own taste. ) Pour contents of glass into shaker and back into the glass to mix well. Garnish with lime. This is one of the most refreshing drinks there is. (If you salt the rim of the glass and you have a "salty dog". Get it?)