Aguas frescas are so simple to make that they hardly call for a recipe, but they weren't in my repertoire before living in Mexico. A step by step instructional is listed below. If you're making agua with any seedless fruit you can skip the strainer.
In recent years, aguas frescas have been completely taken over by sugary sodas. The weekly entertainment mag Dia Siete just put out a great article about the history of aguas in Mexico (click here to read), and the fruits and other unusual ingredients that make them. Recipes included. If you read Spanish, I highly recommend it. For those who don't, I'll translate the opener:
15 years ago, squeezed lime, sweet pineapple, juicy melon, refreshing watermelon or any piece of fruit was mixed with natural water to prepare a pitcher of agua fresca that --at the center of the lunchtime table-- not only hydrated the majority of Mexican families, but also provided many natural nutrients. Today, 8 of every 10 Mexicans consume soft drinks with their meals. As one of the regions of the world with the largest diversity of fruits, it might be worth refreshing ourselves with aguas once again.