What began as nothing more than a party game for adults has, over time, become a household name and a publishing sensation. For 50 years, kids and adults have mined their imaginations, throwing out nouns, adjectives, verbs and adverbs to fill in the blanks and create wacky Mad Libs stories. Self-published by Leonard Stern and Roger Price in 1958, the original Mad Libs has spawned 71 subsequent volumes. Mad Libs sales, which remain strong to this day, total more than 110 million copies. To celebrate the line's 50th anniversary, Price Stern Sloan, now part of the Penguin Young Readers Group, is publishing Best of Mad Libs, a 288-page oversize paperback of 125 stories culled from earlier volumes, and Mad Libs Collector's Edition, a commemorative tin containing the first five Mad Libs books with their original covers.

Price Stern Sloan releases at least six new Mad Libs books annually, some generic and some tied into licensed properties. Licenses can fuel sales impressively: according to Debra Dorfman, president and publisher of Grosset & Dunlap and PSS, 2005's Napoleon Dynamite Mad Libs sold more than 100,000 copies; licensed titles for this spring include Kung Fu Panda Mad Libs and Speed Racer Mad Libs.

The series had a fittingly serendipitous start. Leonard Stern, who has created and produced nearly two dozen TV series, was writing an episode for The Honeymooners in 1953 when Price stopped by. “I was trying to find the right word to describe the nose of Ralph Kramden's new boss,” Stern recalled. “So I asked Roger for an idea for an adjective and before I could tell him what it was describing, he threw out 'clumsy' and 'naked.' We both started laughing. We sat down and wrote a bunch of stories with blanks in them. That night we took them to a cocktail party and they were a great success.” The title was born five years later, when the two overheard an argument at Sardi's between an actor, who wanted to “ad-lib” an interview, and his agent, who declared the idea “mad.”

Yet initially Mad Libs had a bit of an identity crisis. Was Mad Libs a book or a game? “We were turned down by every publisher in the New York area,” Stern said. “Publishers told us it wasn't a book and suggested we approach game manufacturers, but they also rejected us and advised us to talk to publishers. It became a well-worn path.”

Undaunted, the duo found a printer and self-published 14,000 copies. Soon thereafter, Ballantine Books founder (and friend) Ian Ballantine agreed to distribute the book on a short-term basis.

That first printing did not last long. Stern, then head writer and comedy director for NBC's The Steve Allen Show, suggested to Allen that they use the Mad Libs format to introduce guest stars, with the audience supplying words. Allen agreed, and on the next show he held up Mad Libs as Bob Hope was introduced (audience members described the comedian as “scintillating” and dubbed his theme song, “Thanks for the Communists”). Within days, bookstores sold out of Mad Libs.

In the early 1960s, Price and Stern partnered with Larry Sloan, an old high school friend of Stern's, to create their own publishing company. Sloan became CEO of Price Stern Sloan and his partners wrote additional Mad Libs titles, gearing them toward children since much of their fan mail was from kids. With multiple titles landing on bestseller lists and the house's acquisition of other popular properties including Wee Sing, Mr. Men and Little Miss, and Serendipity, Price Stern Sloan grew to be what Stern terms “the biggest publisher west of the Mississippi at the time.” In 1993, Stern and Sloan (Price had died three years earlier) sold their company to the Putnam Berkley Group.

For this spring's Mad Libs milestone, the publisher has created retail displays, a wipe-off board for store events and martini glasses that were mailed to booksellers and media (the inaugural Mad Libs pictured a martini glass on its cover). A new Web site (www.madlibs.com) features games, product information and a widget application for adding Mad Libs games to social networking Web pages.

Looking back, Stern says he had never expected Mad Libs to live this long. “It just proves how important rejection is if you want to get a good start,” he said.