Want a New Career? Take an Encore

"It's a capacity-building organization that uses the skills I acquired on Wall Street," says Orr.

Perhaps the best advice for Boomers interested in encore careers is to choose an issue that is interesting, challenging and evokes passion -- then stick with it. Be committed to the cause and accommodating to the new circumstances.

"You decide malaria in sub-Saharan Africa is your cause," Gomperts says. "Well, if you're really committed, then the cause is more important than the circumstances of the organization in which you work. That accommodating quality and the commitment are likely to be very, very, very powerful in making it a good transition and a good experience."