Depressed by his divorce, burned out at work, Roger Adams was moping in Huntington Beach, Calif., in 1998 when he had a vision. "I saw kids on Rollerblades and skateboards," he says. "It reminded me of a happier time."

It also gave him an idea: Heelys, sneakers with a removable polyurethane wheel that snaps into the heel, allowing the user—leaning back in much the same manner as a skateboarder using only his rear rollers—to segue from running to skating without having to change footwear. Introduced last December, Heelys, which retail for up to $109, have racked up "in excess of $20 million" in sales, says Adams, 47. They are, he adds, "great for getting around Home Depot."

Wheeling and dealing runs in Adams's family. His parents, Roger Sr., 86, and Dolores, 85, operated a roller rink in Tacoma, Wash. , where he learned to skate. But he hung up his skates in high school and had earned a degree in clinical psychology when he had his epiphany.

It took the still-single father of three children, ages 16, 17 and 19, two years of designing and testing—which cost him his three front teeth in a spill—before he brought Heelys to market. Dad, for one, is thrilled that his son is rolling in his footsteps. "Roger never followed skating that close," he says, "but now that he's back into it, it's just wonderful."

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