It's a long wíken ("weekend" in spanglish) here in Puerto Rico as well. A friend of mine, who lives in New York, was quite surprised that we celebrate the Fourth of July here. However, since the Island of Enchantment is officially part of the U.S, it's really nothing out of the ordinary. Besides, who would object to a day off from work? As most Americans celebrate the birth of their country with barbecues and fireworks, so do many people here.
I would say that most Puerto Ricans do not consider themselves to be American, despite having a U.S passport. For the record, those born in Puerto Rico are automatically U.S citizens. However, if you ask a local of what nationality they are, he or she would most likely say "yo soy boricua" (I'm Puertorican). Obviously, there are many American influences here. Not to mention that hundreds of Puerto Ricans serve in the U.S military. There are just so many gray areas in life. For better or worse, I believe most people here know their fate is intricately tied to the U.S.' I think the commonwealth status of Puerto Rico symbolizes a marriage of convenience. Indeed, I find Puerto Rico to be an interesting place because it seems to be in conflict with its own identity. An independence party does exist, but they never seem to gather enough support among the constituency.
On the 4th of July, for most Puerto Ricans, it's a day to relax, and head to the beach. All government agencies, and many local businesses as well, are closed. Have a great 4th!