I don’t know how many times I had to look up a class description because it sounded exactly like another class, but you wouldn’t know they were completely different until you looked up its course description.
Ahh, syntactic ambiguity. Bane of students and CS people.
The thing I had trouble with was when two classes had the same number. CMPEN 461 (communication networks) and CMPSC 461 (programming language concepts); only two letters different! And they were very different courses too. The latter, I would spend 10 minutes on the homework, whereas the former, I would spend 10 hours on the homework. String ensemble was easy to remember because it was a nice even MUSIC 100.