And no, I didn't study; but I did read the textbooks cover-to-cover before the first day of lectures, so I already had a firm grasp on the material before it was presented to the class.
It's not actually that hard. If you have 14 days and your textbook is 700 pages long, that's 50 pages a day, which is eminently possible, particularly if you don't have classes to go to.
Occasionally, I pulled a trick where I went to the first class, grabbed the syllabus, bought the textbook, read the textbook cover-to-cover during the "shopping period" where we could change our classes, dropped the class, and then returned the textbook for a full refund. All the material, 1/6th the time, and none of the money.
Actually, now that I'm employed and have an income, I do basically the same thing: buy the textbook online, read it, and don't bother taking the course. 1/6th the time, 1/50th the money (~$100 instead of ~$5000), and I learn just as much.
As has already been pointed out, I started reading before the first day of classes -- I would usually have most of my textbooks 2-3 weeks before classes started.