What are the most popular student activities/groups?
If you're interested in something, there's probably a group for it. If not, start one! Goups sprout in and out of existence pretty regularly. Right now i'm at least loosely involved/interested with:
Oglethorpe Quidditch League, Get Active Oglethorpe, Oglethorpe Chess Club, OUtlet, Humans vs. Zombies, and Environmentally Concerned Oglethorpe Students - ECOS. These groups hold regular meetings and host events.
Greek life at OU is alive and well. I do not partake, but tons of people do. They have socials and things all the time, but i'm not really into that. Chi Phi has great parties that are usually themed like: Disney, Mardi Gras, or Heaven and Hell. Generally, they do not throw alcohol at everyone. It's more like BYOB and just dance and have fun.
Events at OU happen all the time. There are frequent movie nights, plays(often written by students), and meetings. They have movies on the quad regularly (but can never seem to do them when the weather is right), and trivia nights. Kids host things like ping-pong tournaments, Guitar Hero/Rock Band/Dance Dance Revolution competitions, Bible Study sessions, general study sessions...everything. This really is a good school for leaders. Word on these things spreads quickly on campus.
They go all out for official events. Stomp the Lawn is always good. They bring a mini-carnival to the quad with bungee rides, an obstacle course, mechanical bull, cotton candy, etc...
Boars Head was amazing(look up the history on the OU site). I did not go to the show, but the dinner was really over-the-top. They remade Emerson into a snazzy restaurant kind of deal while a band played, and had delicious food laid out and an open bar for those over 21.
Hogwarts Day is my favorite. That we actually go to Hogwarts is a running joke on campus. Oglethorpe was modeled after Oxford, and Hogwarts was modeled after Oxford, so Hogwarts is Oglethorpe. On HD, they have a Quidditch match on the quad, free food and drinks (butter-beer, every flavor jelly beans, etc), wizard's chess, a sorting hat. Each academic building was assigned a "house," so the science majors wore blue for ravenclaw, art majors wore yellow for hufflepuff, etc. But the best part was how they decked out the cafeteria for dinner to look like the great hall from the movies. Instead of grabbing a plate from the line, they had the food laid out on the tables to be passed around and they gave out delicious chocolate frogs. Oh, and some of the professors dressed up in wizard's robes and sat at a head table, to complete the Hogwarts feel.
They have a casino night every year with an open bar and a live band where you play for chips to win tickets for a lottery. Last year they gave out an ipod, t.v. and tons of other things.
EGGsAM Breakfast: they have this every semester during finals in which some of the professors cook breakfast foods for the students for dinner. A nice pick-me-up during finals when all I want to do is jump out of a third story window.
As far as sports go, i'm not into them. Our golf-team consistently ranks in the top ten, I think.