So this question is a tricky one because my answer is not one that reflects a uniform celebration in Spain, but a cultural difference for a region that is proud to have their own language, customs, and traditions. For instance, a Catalan will cringe if you ask them were you can go and watch a good bullfight. Catalans are against the cruelty matadors impose upon bulls. They will tell you that in their country, meaning Catalonia, bullfighting is for Castilians. If you ask them about flamenco dancing, you can see them twitch as they tell you again, flamenco is for Castilians. In Catalonia, their country, traditional folk dance is the sardana. This is a circular group dance with hands held together up in the air as they gently mark with light foot work in a slow rotation. And if you ask me if Halloween is celebrated here, the answer is no. But I'll get to that when October comes around.
This leaves me with a humble and grand task at hand to answer which traditions, types of food, and celebratory differences or similarities I experience with my American background. Quina feina! (a lot of work)