My topology class has 6 students and all usually sit in the first or second row of the class room. They are NEVER late.
As I walked to the classroom about 1-2 minutes before the start, the lights were out..and of the desks I could see…empty.
I walked in, looked at the back and said “Happy April 1”.
I LOVED it!
I joked that today, we were having the final exam and they had to prove the Tychonoff Theorem from scratch…full version (infinite product of compact spaces is compact in the product topology).
I gave them all 1 extra point on their homework assignments.