Abstract
Body Parts
Humour
100

What is always in front of you but can't be seen?

The future

100
What has 13 hearts, but no other organs?

A deck of cards. 

100

What can you catch, but not throw?

A cold

200

The more of this there is, the less you see. What is it?

Darkness

200

What has one eye, but can't see?

A needle

200

What has to be broken before you can eat it?

An egg

300

What question can you never answer 'yes' to?

Are you asleep yet? 

Are you sleeping?

300

What has one head, one foot and four legs?

A bed

300

What can travel around the world without leaving its corner?

A stamp

400

What can fill a room but takes up no space?

Light

400

I have no feet, no hands, no wings, but I climb to the sky. What am I?

Smoke

400

What belongs to you, but other people use it more than you? 

Your name

500

The person who makes it has no need of it; 

the person who buys it has no use for it.

The person who uses it can neither see it nor feel it.

What is it?

A coffin. 

500

I have two hands, but I cannot scratch myself. 

What am I?

A clock. 

500

What goes up but never comes down?

Your age.