Knock, knock.
Who’s there?
House
House who?
House it going? (How is it going?)
What is worse than finding a worm in your apple?
Finding half a worm! (That means you ate the other half!)
What is the tallest building in the world?
The library of course, it has the most stories!
What is black when you buy it, red when you use it, and gray when you throw it away?
Coal!
Why was the piano player arrested?
Because he got into treble.
What do you get when you drop a piano on an army base?
Flat major.