Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

John is found dead in a bare field. Nobody killed John,
John did not commit suicide.

Inspector Jacob found a bag just a few meters away from John which could save his life. What was in the bag?

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

I shave every day, but my beard stays the same. What am I?

On a bright sunny day, two fathers took their son fishing in the lake. Each man and son were able to catch one fish. When they returned to their camp, there were only three fishes in the basket. What happened?

PS: None of the fish were eaten, lost, or thrown back.

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.

A police officer was passing by when he saw a guy hiding. He walked up to him and genially asked, "What is your name?"

"Shut up!" the boy responded.

"Where are your manners?" asked the outraged police officer.

"Up that tree," said the boy discourteously, directing to a neighbouring tree.

You're looking for trouble, aren't you?" said the police officer.

"No, trouble is looking for me!" the boy answered solemnly.

Why is the boy behaving like this?

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

If 21x = 79x, what is the value of x?