There are no frats or sororities on campus, which I think is great because it means that nobody depends on one source for their social life. But no worries, there are still ample opportunities for partying every weekend, and usually on thursdays too. The 'Sco- the dance club on campus, is actually really fun most of the time, and they offer lots of deals throughout the week like Professor Beers, Slplitchers (which means cheap pizza and pitchers), and quarter beers (self-explanatory). There's a different dj theme each night of the week, as well as pool tables and even a cage for dancing in.
There are a million and one things to do every day, and people often say that oberlin students live 30 hours days because they just never stop doing! My roommate and I co-coordinate the Hunger and Homelessness Campaign for Ohio PIRG (public interest research group), which keeps us VERY busy planning and hosting events on campus, fundraising, volunteering in town, etc. but it's a really rewarding experience. Athletic events are pretty popular on campus, especially soccer, rugby and frisbee.
The dating scene is some murky territory since there is the added factor that you may not know what kinds of people any love-interest is actually attracted to! But overall people seem to do alright- I think it's a pretty typical percentage for a college campus of students who wind up in relationships.
There are a ton of options all the time for activities so students are rarely bored- the administration is EXTREMELY good at programming, which is where a great deal of the student activity fee from our tuition is spent- it's absolutely worth it. People who have come to campus during my last two years have included David Sedaris, Kal Penn, Ishmael Beah, and even Jerry Springer! Really interesting bands come to play, as well, thanks to the very active student union- including Girl Talk and Of Montreal. The Conservatory puts on over 400 performances each school year, which means there is NEVER an excuse not to go to an incredible (and free) concert at least once a month. Once a month the organists put on something called an Organ Pump, which is very exciting but you'll have to come to oberlin to find out what it is!
There isn't a whole lot to do off campus, but if you or one of your friends has a car there's a big movie theater about 20 minutes away and a few big shopping centers not too far either (useful around holiday time). There is of course Cleveland only 20 minutes or so away, and while there may not be THAT much to do there, there is certainly enough, including the Rock & Roll Hall of Fame. There are lots of fun bike trails around campus, too, for when the weather is nice.