Puerto Rico's biggest party, Las Fiestas de La Calle San Sebastian are Puerto Rico's equivalent of Carnaval. Every third weekend in January, people gather in and around the cobblestone San Sebastian Street to make noise—and drink, and eat, and shop, and make noise. And throw some beads, and dance, and make some noise.
Okay, so really, we Puerto Ricans aren't that obsessed with making noise. A lot of Puerto Ricans pride themselves on it, yes, but it's not usually the main appeal of an event.
Noise is just the side effect of drinking too many mojitos (lime juice, rum, mint, and sugar) or Medalla beers. It's the only reasonable reaction to a good meal. Noise is also necessary when you're dancing to the drumming on a street corner because how could you resist singing that old merengue song you haven't heard in ages? (And—I guess—it's useful when you need to attract your friends' attention because you've been dragged away by the crowd.)
Las Fiestas, which originally celebrated a saint like all other festivals in the island (obviously not anymore), are not for the faint of heart. But if you think you can survive it, you should dive into this party face-first because there's just nothing quite like this. (And if you are faint of heart, maybe come during the day when artisans sell traditional Puerto Rican crafts and you can enjoy most of the other nighttime activities at a slightly lower volume.)