Nephew got to be class teacher for one period on Teachers' Day. He gave a surprise test.
Their school lets the students take over for a period on Teachers' Day. My nephew, 11, was given his own class for maths. He prepared for it all week, which should have been the warning. He walked in, told everyone to put their books away, and handed out a ten-question test he'd written himself. He came home very pleased and said it was the best day of school this year.