Greek life and philanthropy actually. Two really big parts of undergrad social life. Anyone can do philanthropy but one needs the time to devote to it and thats hard to do if you work.
Greek life is the bigger one. It's rich kid central and the fees for some Greek groups are larger than the cost of attendance here. "Fiji" for example costs more here than actually going to school here and they have the biggest, nicest house in the campus area (it looks like a plantation). I have a friend at SMU in Dallas (rich kid central in itself) and he rushed. When he was rushing Fiji they asked him what his dad did and if his dad could connect them with job opportunities later down the line. He didn't get too far in the rush process with them.
Greek life is also very, very white and is exclusive for other reasons besides money. Personally, I don't partake in Greek life because I don't see the point in buying my friends and I don't let other people tell me what to wear or how I can and cannot spend my time and with who, however, it's a significant part of college social life - more so at some places than others.
