Kenneth Behring seemed to have everything. He was affluent and generous. But something transformed him during a trip to Vietnam in 2000. The retired construction magnate was helping a relief organization bring food and medicine to a village. It was there Behring personally delivered a wheelchair to a 6-year-old polio victim. The girl's reaction changed his life.

"She got a big smile on her face. She couldn't believe it," said Behring. "It's a sensation I've never experienced with anything else." Inspired, Behring, who used to donate time and money to other charities, created the Wheelchair Foundation, which today delivers 10,000 wheelchairs a month worldwide.

More of today's philanthropists are no longer satisfied with making a charitable donation. They want to see how the money is put to use and perform the benevolence themselves. Behring is part of a new wave of "engaged philanthropists" who choose hands-on involvement over writing checks. Some experts believe that donors who see the impact of their money ultimately give more.