First, pay attention. There is ALWAYS something to learn. If you leave the classroom without a better understanding of some concept or newfound knowledge about a given topic, then you are cheating yourself, not the Prof. Yeah, I said it! No, each and every class will not be a life altering experience. However, there is always something to learn, if you open your mind up to it.
So, what can you do? Ask analytical or critical questions. (Great conversation starter) Some of my most interesting classes and discussions were those in which someone asked the tough question, or asked if we could take a look at the concept from a different vantage point. You can call these individuals “the devil’s advocate.”
If you’re not the individual who asks the tough questions, at least get involved in the conversation. Offer your two cents. Allow your views to be challenged and develop. Let yourself evolve as a student, as a scholar. It’s okay. Really, being involved in your education is okay.
PS: When you participate in conversations in class, the class actually goes by quicker. Real life. I don’t make this stuff up, I just write it.