Got an A in calc, although it was the "calc for non-math majors" calc, not real calc. Flunked AP Calc in high school so any A in calc in college was a massive success...Oh, plus my XC coach was the prof. He was a hell of a classroom teacher. In fact,I still remember a few things from that class (20+ years ago).
Hardest class was Political Theology. Only reason I took it was the course filled a Religious Studies core requirement and fit my ski schedule. Whole semester was so far over my head it wasn't funny. Textbook was about 2500ppg the prof had compiled from numerous sources over the years. I remember sitting there every class wondering what the heck he was talking about. And then when I'd go in for office hours to try to figure it out I still had no idea what he was talking about.
Acoustical Foundations of Music was tough too. This was a Physics elective. I was about as far from science major as you can imagine but was interested in the subject matter so took it as an elective. Class was 5 of us in one of those massive lecture halls that seated 150, so nowhere to hide. Again, this was 2nd semester during ski season. I told the prof I was going to miss 6 Fridays to race and he told me he was going to fail me. Instead of doing that he spent the semester busting my balls. Learned a lot but worked way too hard for a C.