Then they fade into anonymity.

It's a story that Walsh has lived himself — perhaps destined when he was born on Christmas Day 1964 — and chronicled in his book, "The Playmakers," which tells the behind-the-scenes toy stories of some of the world's most beloved playthings, from Flexible Flyers to Beanie Babies.

In the 1990s, Walsh collaborated with two friends to invent the game TriBond, which sold 3 million copies in the 1990s, and followed up with his own, Blurt!, which sold more than 1 million copies.

For Walsh, it has been a happier ending than some of the inventors who have gone before him, leading him to become a full-time game designer and author eager to share his fascination with all things fun. Walsh found many of the founders of favorite playthings to have lived anonymously, at times making hardly any money off their creations that later became cultural icons.

Among his favorite stories is of Eleanor Abbott, who in 1948 was an adult patient in a polio ward in a San Diego hospital and wanted to create something to cheer up the children. She crafted "Candy Land," which in the past 55 years has become so popular that Walsh said it can be found in 60 percent of households with a 5-year-old.

There's also the story of the patriarch of Mr. Potato Head, George Lerner, who came up with the idea to attach plastic features to real potatoes. But in a post-World War II era where memories of food rationing were still fresh, toy companies thought the idea of playing with food would cause a public backlash. Lerner ended up selling his idea for $5,000.

Walsh said some of the inventors he tracked down are happy to remain in the shadow of their famous invention.