When my father was 31 I was 8. Now he is twice as old as me. How old am I?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

It's a test that will check your IQ.

Suppose you have one 11 minute hourglass and one 13 minute hourglass.

Can you measure exactly fifteen minutes using them ?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Role Action
Block Prevents the target player from acting
Redirect Change target player target.
Save Protects the target player from death.
Seer Sees all actions that occurred
Murderer Kills the target player

The following five players are playing:

Andy
Brian
Chris
Daniel
Fred

You are Andy the Seer and you saw the following things:
a) Brian was redirected to Chris.
b) Chris was blocked.
c) Daniel was killed.

Who is the murderer then?

You walk into an old horror house. It has no power or plumbing. Once inside, you see three doors. Each door has a number on it. Behind each door is a way for you to die. Behind door number one, you die by getting eaten by a lion. Behind door number two, you die by getting murdered. Behind door number three, you die by an electric chair. You can’t turn back, so you have to go through a door. Which door do you go through?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?