There's a lot of career-oriented groups at the UPR-RP. Depending on your area of study, you will find The American Marketing Association in Business Administration; the American Medical Student Association and the American Chemical Association in the Natural Sciences, just to name a few examples.
I'm involve with the National Society of Collegiate Scholars, which is an honor society for high-achieving freshmen and sophomores. Nonetheless, once you're in you will always be a member. It's a fun organization because the ideas don't have to be geared to just one area of interest and there's more flexibility with the events we can plan. It's super useful for internships, semesters abroad and jobs later on. Also, there are a lot of benefits like discounts, scholarships and awards. It's been a blast being part of the executive committee.
Most students have apartments off-campus or live at home. I personally have never been to the one building that has dorms for people that don't want to commute because they live far from San Juan (~2-3 hours)
We pay attention to our school teams in the Spring semester during "Las Justas", our mini-Olympic games for all the universities on the island.
We receive a lot of guest speakers from the United States specially in the Natural Sciences field. They come to present their research to our grad students or to the undergrads that are very focused on their research projects.
Also, the school has its own Theater and they alternate between classics and popular pieces throughout the school year. The usually manage to have two pieces per semester.
Dating? There's a lot to choose from and there's something for every taste. But expect all the antics from a "party-school" that is in a "college town".
Most of my closest friends are from high school and the ones I made during my college years I didn't meet in a class.
If I was still a freshman or a sophomore I would probably be in a quaint bar in University St. or in the San Juan area at 2:00AM on a Tuesday. Fast forward to junior and senior year (and you can't wait to graduate), I would probably be in my room studying...for something.
I think the most famous traditions are the "Prepa Week" at the beginning of the school year where freshmen are "initiated" (they make them dance and do stupid stuff in front of everyone---> the irresponsible throw eggs at them) into "La Upi". Also, there's "Las Justas" which I've already explained.
It depends on which type of student you are and what is your field of study. If you are very focused on grades you won't party that much. If you want your college experience to be more than books, people tend to hang out mostly from Thursday to Saturday. Of course, there are people that hang out everyday. If you're in the most demanding areas like Natural Sciences and Architecture you probably won't party as much. If you're in the Humanities or Education area you're schedule may be more flexible.
Fraternities and Sororities are practically non existant in Puerto Rico. I've hear of like one but it's not a very popular thing to do.
Last weekend I was stuck in my house doing final papers and assignments :(
On a Saturday nigh where you don't feel like drinking, you can go dance salsa, go to the movies and right now you have the "county fair" where you can ride on all the attractions and have a good time. Puerto Ricans love to drink and a lot of activities revolve around that but you can find some activities that don't. Also, you can always just say no to alcohol and still go dancing or to a club with your friends that are drinking. People will probably peer-pressure you but you just have to not care what they say and have fun sober (it can be done :) )
Off campus, I love going to the beach, exploring the island (ecotourism), just relaxing at home, ride bikes, go to yummy restaurants and occasionally go out to a bar and have a couple of drinks with friends.