Mean Mrs. Green says that everyone has to invent something for the school science fair. But everyone would rather invent a way to get out of it!

Hubie can't decide on what he's going to do. He thinks all the good inventions have been done already. And all of his friends have figured out what they are going to do. He tries to decide between cloning himself or building a laugh machine. After a bad dream about cloning, he decides to build a laugh machine. After many tries, he makes himself into a human laugh machine and wins a special prize for "Silliest Invention."