Strawberry Watermelon Agua Fresca

"Head into any taqueria here in the West and likely you’ll find agua fresca (translated literally “fresh water”) for sale as well. The standard flavors are tamarindo (made with tamarind), horchata (rice and cinnamon), and jamaica (hibiscus), but you can make agua fresca, a cooling, refreshing drink, from almost any juicy fruit. They were selling this combination – watermelon and strawberry – at Whole Foods today. The samples were so good I had to make some for myself when I got home. I think they would freeze well, too, as a fruit popsicle (without the added water, and maybe a bit more sugar)...."