What is the fastest way to double your money?

Can you place six matchsticks in a manner that each of the matchsticks is in touch with the other five matchsticks?

What can go up a chimney down, but can’t go down a chimney up?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

How can a man go eight days without sleep?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

What four weights can be used to balance from 1 to 30 pounds?

Today, I celebrated my 32nd birthday but I was born in 1972.
How is this possible?

If 2 workers can complete painting 2 walls in exactly 2 hours.

How many workers would be needed to paint 18 walls in 6 hours?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?