best April Fool's joke

A Professor had a rule that if a phone rang in class, it had to be answered on speaker.  The class decided to pull a prank on the professor by having a phone ring and on the other end would be a man claiming to be from a pregnancy center confirming that the girl's pregnancy test is positive.  The girl said that she already knew what she was going to name the baby...first name "April" and middle name "Fools." He did end up laughing along with the class when the joke was revealed but he has since changed his policy. April Fools joke