Funny Sayings & Phrases

Have you ever known one of those people that always has a funny saying or phrase for situations? A childhood friend's dad actuallly would use 'It's colder than a witches tit in a brass bra'.

Where do people learn this stuff? I think it's hilarious. Maybe if you read enough funny sayings and learn old proverbs and euphemisms, then you can whip 'em out next time colorful language is required.