In my Valencian hometown in the late 80’s and early 90’s sangría was a staple in las fiestas del instituto (high school parties); it was the cheapest alcoholic drink available. High school parties took place in bares (bars) and discotecas (clubs) at the end of each of the three evaluaciones (grading periods). Our average age was sixteen. These high school parties generated a lot of anxiety in some teenagers: If you wanted to be guay (cool), you had to drink and smoke a lot. It was not that I did not want to do this, the problem was that I just could not do it. That is one of the reasons high school coolness eluded me. 
Sangría was also the classic drink in las cenas de sobaquillo at home (house parties were each person brings her sandwich). In those occasions, the ingredients were mixed in an unglamourous plastic barreño (wash bowl) by the sangria expert that every group of friends always had. There were then, and there are today, arguments about the authentic recipe. Here you have one that resembles the sangría of my high school years.
Ingredientes (ingredients) y preparación (preparation):
1) Pon en un jarra (put in a jar) 4 melocotones o manzanas en trozos (4 peaches or apples in wedges), 3 cucharadas de azúcar (3 tablespoons of sugar), 1 litro de vino tinto (1 liter of red wine) y 2 naranjas de zumo exprimidas o el zumo de dos limones (2 squeezed oranges or the juice of 2 lemons).
2) Déjalo en la nevera durante 2 horas (leave in the fridge for 2 hours).
3) En el momento de servirla (at the moment of serving), añádele (add) mucho hielo (a lot of ice), gaseosa (Ginger ale) y Cointreau o ron (triple sec or rum) opcionales (optional) - depending on the preference for sangría fuerte (strong) or floja (weak).