One the night of June 23rd the Spanish pay tribute to the Summer solstice with the fiesta of San Juan. Although not on the mainstream calender as being one of Spain's great fiestas it is in fact one of the most celebrated nights in the whole year, second only perhaps to new years and Christmas Eve, although the latter is more of a quiet family affair rather than the fun and excitement that can go on all night with the San Juan Fiesta.
The festival of San Juan ( named after John The Baptist ) goes back 5000 years and is an ancient pagan festival.
As the sun sets on the eve of the 23rd everyone heads for the nearest beach where they build bonfires, light barbecues, prep the food including fresh sardines, kebabs and other tasty morsels, fill buckets with ice and drinks and have fun .
Here is an excellent video of the San Juan Fiesta. http://www.videojug.com/film/spanish-festival-night-of-san-juan