Knock Knock Who's there? Adolf! Adolf who? Adolf ball hit me in the mouth! 1690. Knock Knock Who's there? Aesop! Aesop who? Aesop I saw a puddy cat! 1691. Knock Knock Who's there? Abe! Abe who? Abe C D E F G H...! 1692. Knock Knock Who's there? Abyssinia! Abyssinia who? Abyssinia behind bars one of these days! 1693. Knock Knock Who's there? Alberta! Alberta who! Alberta'll be over in a minute!