Good Riddles

Question: In Michigan you cannot take a picture of a man in a green hat.

Why?

Question: What grows up and down at the same time?

Question: A man drops an egg onto the cement. The egg doesn't break after falling 3 feet.

How could this be?

Question: A teacher decides to give a pop quiz one day but all of her students refuse to take the quiz thinking that the teacher will call off the quiz. She can give only one of these students a detention for skipping the quiz. All of the students know each other's names and if a student knows he/she is getting a detention they take the quiz.

How can she threaten her students with the single detention so they all take the quiz?

Question: What is the best way to keep your hat from falling off your head?