Since Madison is a large school with hundreds of majors, classes vary greatly depending on what you study and the amount of coursework you choose to do each semester. This being said, I think that classes in general are challenging, but also rewarding. Introductory and survey classes usually consist of lectures, taught by professors, and a discussion or lab led by a TA. I've never had a TA teach a lecture; professors lecture, answer questions, and even administer tests. In discussions and labs, TAs help us understand lecture material, and we often do exercises and activities to expand upon the material we learned that week.
This is true for most of the classes I have taken for my English and psychology majors thus far. In my literature classes, discussion is a time for closer examination of text, advice about writing essays and taking exams, and group discussion of things we touched on in lecture. The same is true for many of my psych discussions, in which we discuss possible social implications of lecture topics, TAs answer questions and give advice about the material, and students work together to thoroughly understand tough concepts. As you get increasingly specialized within your major, classes generally get smaller and more specific--which provides ample opportunity to interact more with professors.
Psychology is the biggest department on campus, with more students choosing to study how the mind works than anything else. One of my favorite classes was Introductory Psychology, the basic class required for all psych and business majors. It was a lecture of about 200, and a discussion of 15 students and 2 TAs. Discussion was helpful because we did hands-on activities to understand things the professor said in lecture, and I remember giving and listening to presentations about specific topics. In this way, you get the professor's lecture, which usually matches the textbook and emphasizes material on the test, and you also get help from your peers and TAs in a more concentrated environment.
Class participation is central to discussions and labs, in which group discussions are the main focus of the 50-minute classes. Professors encourage student questions in lecture as well. For psychology in particular, students discuss topics outside of class all the time. We see things that we study at work in real life, and it's fun to be able to talk about it with a friend in your class and see that your work has paid off.
Overall, classes are challenging yet interesting, and I have found professors and TAs to be very helpful and available. Students are not overly competitive, and we get through tough classes by utilizing the resources available to us and by working together.