This and other similar fruit drinks, which translate literally as "fresh water," are served all over Mexico and they're a cinch to replicate at home. The key is to strain the pulpy fruit to make a clearer liquid. Instead of melon, you could use strawberries, pineapple, or mango -- any fruit that is soft enough to puree.
Puree cantaloupe and pour through a fine sieve to eliminate pulp. In a pitcher, mix strained fruit puree with water and season with sugar and lime juice, to taste.