What is the riddle which can be asked all day with a different correct answer each time.

A Shopkeeper sold a few chickens to four different customers on a particular day. It was such that each customer purchased half of the remaining chickens and half the chicken more.

Can you find out how many chicken were sold by the shopkeeper on that day if we tell you that the fourth customer bought a single chicken ?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Can you start the fire using two pieces of wood?

Three fair coins are tossed in the air and they land with heads up. Can you calculate the chances that when they are tossed again, two coins will again land with heads up?

Solve the following series:
AZ, GT, MN, __, YB

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

You stand in front of two doors. A guard stands next to each door. You know the following things: one path leads to paradise, the other leads to death. You cannot distinguish between the two doors. You also know that one of the two guards always tells the truth and the other always lies. You have permission to ask one guard one question to discover which door leads to paradise. What one question would you ask to guarantee you enter the door to paradise?