If you are craving a glass of fresh squeezed lemonade, but only have a couple of lemons, or maybe even only one, never fear: Lifehacker's Claire Lower says "a single lemon is all that you need to make a perfect glass of lemonade."
First, you'll need simple syrup, which you can buy or make yourself, by boiling two cups of sugar in two cups of hot water, and then cooling. Pour into a bottle and store for other uses (like sugar in your tea or coffee.) Now squeeze the juice of one lemon into a pint glass with 1 tablespoon plus 1 teaspoon of simple syrup and 12 ounces of water, adding more syrup if it's not as sweet as you like it.
Shake in some cocktail bitters or ginger brine if you want, and add ice.