1/2 cup pineapple, peeled and chopped
1 lime, rinsed, quartered and seeded
1/2 cup baby spinach, lightly packed
1/4 cup sugar
3 cups water
Ice cubes, as needed

Combine the pineapple, lime, skin and all, spinach and sugar in a blender with 3 cups of water. Blend until it is very smooth, and then strain through a sieve into a large pitcher. Gradually season the agua fresca to taste with more sugar and stir thoroughly, then pour the agua fresca into ice-filled glasses, and serve immediately.