During which month do people sleep the least?

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary, you'd think nothing was wrong with it. Actually, nothing IS wrong with it. But it is not as ordinary as you might think. If you think about it for a bit, you will find out why it is truly so unusual. So what is it? What is so unordinary about this paragraph?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

How can you take 2 from 5 and leave 4?

How many times can you subtract the number 5 from 25?

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?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

The dirtier I get, the whiter I look. Who am I?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?