Times have changed since the days when an imaginative kid was happy to play with an empty cardboard box. Today, about 2.6 billion toys are sold every year, creating a $20.3 billion industry. It seems that every decade manufacturers create a toy that launches a buying craze. Some just flash past on their way to a rummage sale table; others are timeless treasures. So without further ado, here are some of the best toy fads of the 20th century.

1950s

1. Silly Putty was developed in 1943 when James Wright, a General Electric researcher, was seeking a synthetic rubber substitute. His silicone-based polymer was elastic, could bounce, be easily molded, and always held its shape. Parents liked the fact that the putty was nontoxic and nonirritating. Since its debut as a toy in 1950, more than 300 million eggs of Silly Putty have been sold.

2. In 1943, naval engineer Richard James stumbled across an invention that would become a beloved toy worldwide. Made of 87 feet of flat wire coiled into a three-inch-diameter circle, the Slinky could "walk" down stairs when one end was placed on one step and the other on the step below. The classic slinky really took off in the 1950s, and today more than 300 million of the simple-yet-clever toys have sold worldwide.

©2007 Mattel Barbie was created in 1959.

3. Mr. Potato Head, with his interchangeable facial features, was patented in 1952 and was the first toy to be advertised on television. But for the first eight years, parents had to supply children with a real potato until a plastic potato body was included in 1960.

4. Intending to create a wallpaper cleaner, Joseph and Noah McVicker invented Play-Doh in 1955. Initially available in only one color (off-white) and in a 1.5-pound can, Play-Doh now comes in a rainbow of colors. The recipe remains a secret, but more than 700 million pounds of this nontoxic goop have sold since its introduction.

5. The concept of the hula hoop had been around for centuries. Then, in the late 1950s, Wham-O, a maverick California toy company, rolled out a plastic hoop for swivel-hipped kids. The concept caught on and 25 million sold in the first six months. They cost $1.98 each, and, by 1958, 100 million of them had been sold around the world -- except in Japan and the Soviet Union where they were said to represent the "emptiness of American culture." Ouch.

Barbie leads off the list of toys continued on the next page.

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