Good Riddles

Question: Why don't most buildings have a 13th floor?

Question: What English word is always spelled incorrectly?

Question: Two men are facing each other alone in a large room. There is a clock on the wall. One man, who thinks of himself as a prophet, says to the other, "In five minutes you'll be stabbed in the back."

The other man is very distraught and stares at the clock. After five minutes he is stabbed in the back.

What happened?

Question: For now I must stay under the man who made me,
but when he dies I'll be as powerful as he.
They will watch and listen to what I say,
then some of their money to me they'll pay.

Who am I?

Question: A man and his son are in a terrible accident and are rushed to the hospital in critical care. The doctor looks at the boy and exclaims "I can't operate on this boy, he's my son!" How could this be?