Another drink that is overlooked is agua miel.
Water honey
The base for pulque. The classic beverage of old Mexico. On major highways if you see young men standing on the shoulder surrounded by an assortment of reclaimed bottles, he is likely selling agua miel. It has to be kept refrigerated and even then has a shelf life of just a few days. Fermented agua miel is called pulque. But the fermentation is accompanied by exotic enhancers (whole sugar, raisins, chanting and strict exclusiveness that prohibits strangers from entering the building). Sweet pulque lasts about three days before turning decidedly sour. Endless experimentation still goes on to find a way to bottle this stuff -- the recipe would be the Holy Grail of pulque.