How is the moon similar to a dollar?
If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?
There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence. Do you know what word is that?
Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?
John said, "If yesterday was tomorrow, today would be Friday." When did John make this statement?
As a whole I am both safe and secure. Behead me and I become a place of meeting. Behead me again and I am the partner of ready. Restore me, and I become the domain of beasts. What am I?
They came out at night, without being called. They lost at day, without being stolen. Who are they?
When my father was 31 I was 8. Now he is twice as old as me. How old am I?
Look at me. I can bring a smile to your face, A tear to your eye, Or even a thought to your mind. But, I can't be seen. What am I?
In which direction should the missing arrow point?
What work can one never finish?
In 2007, a puzzle was released and $2 million prizes were offered for the first complete solution. The competition ended at noon on 31 December 2010, with no solution being found. Wiki