Over 200 Knock Knock Jokes For Children Knock, Knock.Who's there?Justin.Justin who?Justin time for lunch. Plenty more like that and children in the family will love these knock knock jokes. Perfect as a gift, for long car journeys or just for amusement. Tags: knock knock books, joke book, knock knock jokes for kids, knock knock jokes, knock knock jokes for kids aged 5-7, knock knock kids book, knock knock quote book, jokes book, jokes book for kids,...