I am an odd number. Take away a letter and I become even. What number am I?

On a certain day, John celebrated his birthday. Two days later, his older twin brother Jacob celebrated his birthday.

Is this even possible? How can it be?

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

You are given four tennis balls and asked to arrange those balls in a manner that the distance between each one of them is exactly equal. How will you do it?

What do you think with the below Picture ?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

There was a strange boy who was born before his father. How can this be possible?

There are forty elephants and they have forty-fore heads. How can this be possible?

Can you divide the below-given shape into four equal and identical pieces?

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?