How can a man go eight days without sleep?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

The centre of the third figure is empty. What digit should fit inside?

What is the last thing you take off before bed?

Can you find out the missing number in the grid?

If two's company, and three's a crowd, then whats four and five ?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

A time long back, there lived a king who ruled the great kingdom of Trojan House. As a part of the renovation of the kingdom to meet future security needs, he asked his chief architect to lay down a new play in a manner that all of his 10 castles are connected through five straight walls and each wall must connect four castles together. He also asked the architect that at least one of his castles should be protected with walls. The architect could not come up with any solution that served all of King's choices, but he suggested the best plan that you can see in the picture below. Can you find a better solution to serve the king's demand?

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?