Amazon has The BIG Book of Riddles for Kids: An Interactive Joke Book That is as Much Fun to Play With as it is to Read (The BIG Book Series) [Normally $2.99] for $0.00.
What do you call a funny book about eggs?
A yolk book!
What goes up but never comes down?
What kind of pet always stays on the floor?
Why was the belt arrested?
For holding up the pants!