What’s black and white and read all over? A pair of little books, Laugh Out Loud Jokes for Kids and Knock Knock Jokes for Kids, which have held the #1 and #2 spots on Amazon’s Children’s Joke & Riddle Books list for the past several weeks.

Baker Publishing Group national sales manager Rob Teigen, publishing under the pen name Rob Elliot, created the books with his wife, Joanna, and their four children, now 20, 16, 13, and 10. “Every night we’d sit around the dinner table and come up with the jokes,” Teigen says. “The kids would bring jokes home from school and we’d have fun tweaking them and coming up with plays on words.” He adds, “There is nothing more enjoyable than seeing kids and adults laugh together.”

Laugh Out Loud Jokes for Kids was originally published in a mass market edition by Baker’s Spire/Revell imprint in 2010; Knock Knock Jokes for Kids came out from Revell in 2013. Laugh Out Loud sold 128,585 copies in November and December, for total lifetime sales of more than 450,000; Knock Knock sold 110,973 during the same period, for total sales so far of 180,000. LOL was Amazon’s #20 print title for 2013.

A new book in the series, Zoolarious Animal Jokes for Kids, was released in 2012 but is being republished as Laugh Out Loud Animal Jokes for Kids in February. A trade paper edition combining all three books, The Big Book of Laugh Out Loud Jokes for Kids, released this month.

Teigen says the royalties from the books—priced from $4.99 to $9.99--are helping fund his son’s college education and will help with his daughters’ expenses in the future.