Knock Knock Jokes are a type of humor that follows a simple call-and-response format. One person starts by saying "Knock, knock," and the other responds with "Who's there?" The first person then provides a name or phrase, leading to a pun or play on words when the second person asks for more information. These jokes are popular among children and adults alike due to their straightforward structure and often silly punchlines. They encourage interaction and can be easily adapted to various themes, making them a fun way to engage with friends and family.