During which month do people sleep the least?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

What has many keys but can’t open a single lock?

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

John was piloting a plane behind a car but was never able to overtake it. Why?

Can you name any English verb that becomes its past tense by simply rearranging the alphabets ?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?