Most people seem to be just surviving. But there a decent amount of people who hack on things frequently, and a small, but still sizable number of very prolific hackers. There are some people that comfortably take 8 or more classes a semester. Certainly some of those types of people choose to take a normal course load and have a lot of time to hack. But it seems like the more common situtation is that you end up neglecting your schoolwork and getting poor grades.
