Back in the days I was a 1st year student at my uni, I participated a set of lectures given by quite an extraordinary professor. He was an eccentric guy, a showman, very full of himself - not surprising since he is an expert in his field. He spent (and probably still does) half of an academic year in the US, teaching at Iowa University, and for the second half he always came to Poland (he’s a Pole, btw).
As I said, he’s an eccentric guy. And so were his methods of lecturing. For instance, we were repeatedly told that his favourite book is “Potop” (”The Deluge”) by Henryk Sienkiewicz, and that we should expect questions related to it on the final exam (I studied English, and the lecture was by no means connected with literature).
Those lectures took place in the summer term. One day I received a text message from a friend - very concerned, a bit frightened even - telling me that the newest it had been confirmed that on our final we’re going to get obligatory questions on the whole trilogy by Sienkiewicz. At first I though: what the heck, are you joking? But then I remebered current date: yup, it was 1st April. They were indeed joking.
I sent this message to several people, and to my surprise some of them believed me. I guess it was the first and the last time I managed to deceive people during April Fools.
But yeah, the final test had two or three additional questions concerning “Potop”. Those were the days, my friend...