What you cannot hold but it is yours?

What is the riddle which can be asked all day with a different correct answer each time.

Different lights make me strange by changing me into different sizes. What am I?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

Sahir enters the bank aims to rob and finds Jai standing inside armless. He aims a gun at him and asks him the code for the safe. Jai says, 'The code is different every day but if you hurt me, you will never get to know the code'.

Sahir pins him down and ties him with a rope. He then inserts the safe code and easily takes all the money with him.

How did he know the code?

Can you write down eight eights so that they add up to one thousand?

On this table for two, something is missing for the other one. Your task here is to find the food item that does not have its pair on the table.

That attorney is my brother, testified the accountant.

But the attorney testified he didn't have a brother.

Who is lying?

Two old friends, Jack and Jill, meet after a long time, and discussing as:

Jack: Hey, how are you, man?

Bill: Not bad, got married and I have three kids now.

Jack: That's awesome. How old are they?

Bill: The product of their ages is 72 and the sum of their ages is the same as your birth date.

Jack: Cool..But I still don't know.

Bill: My eldest kid just started taking piano lessons.

Jack: Oh, now I get it.

How old are Bill's kids?

This is the oldest riddle that I have heard.

Once there was a man who was travelling with a Tiger, goat and grass.
He needs to cross a river that can carry a maximum of two i.e. Man + one of Tiger goat or grass. But the problem is "If he takes the lion with him, the goat will eat grass and if he takes grass with him, the lion will eat the goat".

How can he ensure the safe delivery of all three?