It's finally gotten hot in the Netherlands, by which I mean, "I occasionally break a sweat when running around while wearing jeans." Summers in the Netherlands are mild, generally, and so the full power of the following drink is probably lost here. Nevertheless, it is delicious, refreshing, and you can make it as healthy or unhealthy as you'd like.
~ 1 C of basil leaves, chopped fine
Sugar (at least 1/2 C is recommended)
A few hours
Mix the chopped basil leaves with the sugar, bruising the leaves.
Squeeze the juice out of the lemons. If you're using one of those citrus juicers that can cut into the rind, make sure you don't cut into the pith.
Mix the sugar/basil mix with the lemon juice. Let it sit for ~10 minutes. This allows the essence of the basil to be captured by the acid of the lemon juice. It goes without saying that you should not let this sit in an aluminum bowl. Use glass or ceramic. A cereal bowl works really well.
Seive the sugar/lemon juice/basil mix into the pitcher. Pour water through the sieve to fill up the pitcher. Chill. Drink.
Makes ~1 qt.