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?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

I’m tall when I’m young, and I’m short when I’m old. What am I?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

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

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

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