Question: How do you know if there's and elephant under your bed? Answer: You bump your nose on the ceiling! This is an example of the very funny, clean jokes for kids you will find on the "Jokes Galore!" page of the National Institute for Environmental Health Sciences website.
The website for the American Grandparents Association (Grandparents.com) also contains kids' jokes and riddles with hilarious one-liner answers. For a wider variety of jokes and riddles kids can enjoy and re-tell, including jokes of the infamous "Knock Knock" genre, go to Funology.com. Ducksters.com is another website that is careful to be certain its content is appropriate for kids. The jokes and riddles on this site touch both the esoteric and the simple ends of the silliness spectrum!