John is a strange liar.

He lies on six days of the week, but on the seventh day, he always tells the truth.

He made the following statements on three successive days:

Day 1: "I lie on Monday and Tuesday."
Day 2: "Today, it"s Thursday, Saturday, or Sunday."
Day 3: "I lie on Wednesday and Friday."

On which day does John tell the truth?

Why is it very easy to weigh a fish?

How can you leave a room with two legs and return with six legs?

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary, you'd think nothing was wrong with it. Actually, nothing IS wrong with it. But it is not as ordinary as you might think. If you think about it for a bit, you will find out why it is truly so unusual. So what is it? What is so unordinary about this paragraph?

Which tank will fill first?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

Remove two matchsticks to make the below equation correct.

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?