Why does a room full of married people look so empty?

Because there's not a single person in it.

Little Johnny turns up late for school one day and his teacher asks why.

Little Johnny responds, "It's snowing heavily outside, so every time I took one step forward, I slipped two steps back."

"Well, how did you make it to school then?"

Little Johnny sighs, "I got fed up, so I turned to go home."

Knock, knock

Who's there?

Little old lady.

Little old lady who?

I did not know you could YODEL!

Where do you find giant snails?

At the end of a giant's fingers.