You Know, for Kids!

Richard Knerr, co-founder of Wham-O Inc., which unleashed the granddaddy of American fads, the Hula Hoop, on the world half a century ago along with another enduring leisure icon, the Frisbee, has died.

A treasure chest of dozens of toys followed that often bore playful names: Superball, so bouncy it seemed to defy gravity; Slip 'N Slide and its giggle-inducing cousin the Water Wiggle; and Silly String, which was much harder to get out of hair than advertised.

When a friend told Knerr and Melin about a bamboo ring used for exercise in Australia, they devised their own version without seeing the original.

They ran an early test of the product in 1958 at a Pasadena elementary school and enticed their test subjects by telling them they could keep the hoops if they mastered them.

They seeded the market, giving hoops away in neighborhoods to create a buzz and required Wham-O executives to take hoops with them on planes so people would ask about them.

Wham-O soon was producing 20,000 hoops a day at plants in at least seven countries, while other companies made knockoffs. Within four months, 25 million of the hoops had been sold, according to Wham-O.