In Greek mythology, the Sphinx sat outside of Thebes and asked this riddle of all travellers who passed by. If the traveller failed to solve the riddle, then the Sphinx killed him/her. And if the traveller answered the riddle correctly, then the Sphinx would destroy herself. The riddle:

What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Oedipus solved the riddle, and the Sphinx destroyed herself.

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

Which number should replace the question mark?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

When 99 is considered higher than 100?

I have feet, but no legs. Which animal Am I?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

A man was driving a black truck. His lights were not on. The moon was not out. A lady was crossing the street. How did the man see her?