The 12 Grapes of Noche Vieja, New Year's Eve
At the stroke of midnight, Spaniards eat one grape for each toll of the clock. They observe this century-old ritual (which began after a spectacular harvest) whether they're at home, in a packed restaurant in Barcelona, or in Madrid's Puerta del Sol, where the grape-eating countdown, like the ball drop in Times Square, is televised.
The essence: The good harvest is celebrated in the hope of attracting luck and riches in the coming year.
Asalto, a Traveling Caroling Party, Christmas Season
In this slowly growing party, a version of Christmas caroling, friends show up unannounced at one another's front doors, singing and playing instruments. They're invited in to sing, dance, drink, and eat (a typical dish is the traditional asopao de pollo, or chicken-and-rice stew) until it's time to bring their host to the next house. The revelry moves from house to house until dawn, when everyone heads home.
The essence: An invocation of the spirit of friendship and fun.