Put 4 c sugar and 2 c water in sauce pan and bring to a boil.
Boil for about 2 minutes to dissolve the sugar.
Turn off the heat and add about 2 oz fresh basil. Stems and all! You want to let this steep for about 30 minutes.
While that is cooling a bit, take the juice of about 8 lemons, about 2 cups total.
Whisk together about 2.5 cups of the basil syrup plus 4 cups cold water, and the 2 cups of lemon juice. You can sweeten it to taste or even use a natural sugar like honey or stevia!