With the nice weather , there are at least four fruit stands set up near Royal Nepal in the Del Ray section of Alexandria. I tried three agua frescas form tow of the stands.
One had mango and a cucumber-lemon mixture. The mango was intense, almost like drinking a mango puree, and probably could use some more water to thin it. The cucumber-lemon was a five-star HO delight. Great zing to it. But you might have to get lucky as I am not sure any of these are out at all times. The next time I dropped by, that vendor did not have their agua frescas.
Just a few steps, down, I went for an agua fresca of papaya-pineapple-yellow cherry. This too was surprsingly thick and intense. I wound up taking it home to thin it, and that worked perfectly. Wicked, complex flavor.