I think the most popular groups are sororities/frats, RAs/Orientation counselors (OCs), Crossseekers/Intervarsity, ABTech, SDC, SWE, organizations specific to ones major. It depends on what dorm you live in, if you live a predominatly freshman dorm, the doors are left open all the time, but when it comes to upperclassmen, they're not trying to make new friends:) and the doors are barely ever left open. Athletic events are getting more popular, but not as big as a Division I school. Its mainly athletes and their friends supporting other athletes. The school movie is big b/c its cheap, so if they're showing a good movie, a lot of people will be there. Also, when there are really famous guest speakers like Bill Gates, there are huge lines to get in, but for other speakers they are usually specific for certain majors (not exclusive but lecture topic) and mainly graduate students/facult/staff go even though undergraduates are welcome. I think a lot of people date at CMU, for me I havent found anyone my type (mainly b/c I don't have time) also there are several other universities that people branch out to to find their potential mates, 2 of my closest friends boyfriends are from University of Pittsburgh, which is by the way literally a block away. I met my closest friends from the volleyball team and mainly from my dorm freshman year, but as the year progressed some people from my major became my closest friends as well. I usually am never up that late (which is not the case for most people), but if I am finishing a huge assignment. Annual events/traditions are Spring Carnival: (Buggy, Booth and freetime), Lunar Gala Fashion show, Spirit Fashion show, Mayur show, Dancer's Symposium, Winter Gala, Chili Cook off, Mobots, National Engineers Week, Greek Sing, Mr. Fraternity, the list could go on. I think people party a lot especially when the fraternites are not on probation. If they are there are a lot of house parties. Frats/Sororites are big only if you want to join one, if you don't (which most people do not want to) they are only useful for parties. Last weekend I went to my friends house (who now lives off campus) and a bunch of us made dinner and watched a movie. On Saturday night besides drinking, there are many things one can do: Aerobics classes in the gym, UC Late night (event every weekend which is free), watch a play put on by the drama school, go to the movies, shopping, bowling, out to dinner, etc. I unfortunately havent had much time to do stuff off campus yet, but a lot of other people do, (it may just be me) but their a lot of museums and cool stuff Pittsburgh has to offer.