It's difficult to say what the most popular student activity is. Most students like the outdoors. I would consider myself pretty involved with campus. I am a part of student government, serve on a board that oversees campus organizations, and am a club president. We have over 150 clubs on campus, so it's easy for students to find what they like or learn about something they've never done before. It's also very easy to start your own club on campus if you can't find what you're looking for. Athletic events are somewhat popular. The bigger the crowd at events, the more fun the event is. There are tons of events around campus including a movie every Thursday and a comedian on Fridays. Homecoming always has great events. E-Days in particular is a blast. There's a concert, comedian, fireworks, all on campus. E-Days is really the event everyone is waiting for the entire year. Because the community around campus is so small, it's very easy to meet people. The down side is that it's hard to meet new people once you've met everyone. Fraternities and sororities tend to make their own communities, which can be a good thing, but also doesn't lend itself towards meeting new people. Weekends can be dull, but can also have a lot going on. Mines students are predominately male, which gears the party scene more towards drinking as opposed to meeting people. There are many times were students just don't have time to party on the weekends because they have too much to get done. There are also student that just don't really enjoy partying. Bowling is a popular thing to do and is pretty inexpensive. Off campus activities are mostly outdoor activities. Mines has an Outdoor Rec Center that has tons of equipment for students to borrow. They also offer classes to learn rock climbing or bike tune ups.
Colorado School of Mines has more clubs than any other School in Colorado. If you can't find something to join that you enjoy doing you are not looking hard enough. It is also a simple process to start your own club or student organisation. Yearly we have Homecoming and E-days which students enjoy. There are fireworks shows, comedians, movies, improv nights lets just say there is a lot going on on campus. You just have to be willing to go out and do it. CSM also has a great Greek Community that promotes strong academics, community service/philanthropy, and developing high quality individuals. I highly suggest checking it out Greek life and attending a few events.
As a student at mines, Intramural Sports are huge! IM sport leagues for students can act as an outlet from the rigors of study and our IMs are well organized and offer something for everyone. Mines has a great student council. They typically organize a least two social events a week, whether it's a new movie in the Student Center or a comedian on a Friday night, student can always find something to do. Golden is in a great spot; we're 20 minutes from Denver and about an hour from the major ski resorts. Most importantly the Coors Brewery is located in Golden, where you can go and get complementary drinks!
There are very few social activities at the school of mines. The city of golden for the most part shuts down at about 8:30 or 9 so there is nothing to do besides going to a bar or an 11 dollar movie.