In a medium saucepan, bring the sugar and 2 cups of water to a simmer until the sugar melts.
While the sugar is melting, squeeze the fresh lemons until you reach 1 1/4 cup lemon juice.
In a pitcher, add in the lemon juice, 4 cups cold water, sugar mixture.
Stir to mix, add slices on lemons and ice when you're ready to serve.
Notes
To make a spiked version of lemonade add in 1/2- to 1 cup vodka or gin.You can also leave a bottle of vodka next to the lemaonde so guests can spike their own.