It sounds like the usual setup for a knock-knock joke: Who is the best-selling author on all of Amazon.com this holiday season? Rob Elliott. Rob Elliott who?
Yet it's no laughing matter for Rob Teigen, a father of five in Grand Rapids, Michigan who, under the pen name Rob Elliott, currently owns the No. 1 and No. 2 spots on Amazon.com's best-selling book list, outpacing such hits as "Unbroken" and the latest from Bill O'Reilly.
The source of his success: two books, "Laugh-Out-Loud Jokes for Kids" and "Knock-Knock Jokes for Kids," both of which are aimed at parents and grandparents looking for help now that their six year olds are just discovering the art of telling jokes, but have awful material.
"I can't tell you how many people have come up to me and said 'You saved my life,'" Teigen says.
Not that all of Teigen's jokes are gems, he is quick to add. Most of the material wouldn't be out of place in a Jackie Mason show. (Example: "Who keeps the oceans clean? The mermaid." )
Yet even a groaner like that is likely to top whatever a kindergartner will come up with by himself, a concept that Teigen, 45, learned by experience. He began writing his first book in 2009 when his youngest daughter was six and desperately wanted to tell jokes around the dinner table, but struggled to understand the concept.
"She would spout off what she thought were punch lines and you'd laugh while thinking 'That doesn't make any sense'", Teigen said.
Each year, there's a new set of parents and grandparents in the same predicament, which explains why Teigen's "Laugh-Out-Loud Jokes for Kids" hit No. 1 on Amazon last holiday season, too. Each book is priced at $4.95 - and $2.99 for the e-book version, a low enough price point to make an inexpensive stocking stuffer.
"Laugh-Out-Loud Jokes for Kids," his top-seller, has sold more than 385,000 copies overall, with 90,000 this year alone, according to Nielsen BookScan, which tracks approximately 80 percent of U.S. book sales. About 70 percent those sales came via Amazon over the holiday season, Tiegen said.
Impulse-buying aside, Teigen looks to have honed in on something that scientists who study humor are still puzzled by.
Research suggests that children start to appreciate that a word with multiple meanings can be funny around the age of seven, said Peter McGraw, a professor of marketing and psychology at the University of Colorado who runs a lab dedicated to researching humor. Before that age, physical comedy and tickling tend to elicit more laughs, though scientists don't quite know why, he said.
"There aren't any joke-telling Mozart's. You don't have three year olds who can tell great jokes because they haven't reached that development stage yet," McGraw said.
As a result, children tend to really like puns and other punch line-driven driven jokes until around the age of 12, when they discover sarcasm and master it by the time they are full-blown teenagers, said Scott Weems, a cognitive neuroscientist at the University of Maryland and the author of "Ha! The Science of When We Laugh and Why."
Humor, it seems, is even more complex than it appears.
Weems, whose favorite movie is the stoner comedy "Harold and Kumar Go To White Castle," said the higher-level thinking that goes into appreciating humor has long stymied engineers attempting to create realistic artificial intelligence programs.
Research scientists at the University of Aberdeen in Scotland, for instance, are behind a website called the Joking Computer (http://www.abdn.ac.uk/jokingcomputer/joker.shtml) that is a repository of computer-generated jokes and asks visitors to rate whether each one is truly funny.
Even if software somehow grafts a funny bone, Teigen doesn't have much reason to worry. He earns just pennies for each book he sells. For his day job, he works at his publisher, Baker Publishing Group, an Evangelical house based in Grand Rapids, Michigan, where he is the only sales rep who can say he's sold more than 1.3 million books himself.
He has plans to expand his line of joke books, and is thinking about trade marking "Laugh-Out-Loud Jokes" as his own brand. But Teigen doesn't expect to write any more knock-knock jokes. He struggled to fill the book, he said, and had to turn to a baby name book to come up with new material for wordplay. Besides, parents - his real customers - might turn against him.
"Kids love my knock-knock jokes," he said. "But after about 400 of them, parents hate me."