We had them all the time at college. So much for coursework eh? I remember once we were in numerolgy class and we were chatting away. The tutor came over, she had a look on her face which told me she was going to tell us to stop chatting and get on with our work. She came over just as we were talking about the expansion of the universe. She stod for a second, heard what we were talking about and walked away.
I think I was the only one who saw it but to this day it makes me laugh.