What has one letter and starts with an E?

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?

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

He digs out tiny caves and stores gold and silver in them. He also built bridges of silver and made crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs his help, yet many people are afraid to let him help them. Who is he?

If eleven plus two equals one, what does nine plus five equal?

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

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

I have a big mouth and I am also quite loud! I am NOT a gossip but I do get involved with everyone's dirty business.

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?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.