Knock-knock joke
The knock-knock joke is a type of audience-participatory joke, typically ending with a pun. Knock-knock jokes are primarily seen as children's jokes, though there are exceptions. The scenario is of a person knocking on the front door to a house.
Knock Knock Joke People (First 5 people) - Page 0
Lots of Knock-Knock Jokes for Kids
Book by Whee Winn
Knock Knock Who's There: My First Book Of . . .
Book by Tad Hills
Knock, Knock! Who's There?
Book by Anna Ross
Knock Your Socks Off: A Book of KnockKnock Jokes
Book by Michael Dahl