What work can one never finish?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

During which month do people sleep the least?

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?

What is the below Rebus indicate?

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

Prove that twice of ten is the same as twice of eleven.

Using eight eights and addition only, can you make 1000?