A "3G" retirement — golf, gossip and grandchildren — isn't for everyone. Restless minds look for more ways to engage the world. One outlet is volunteerism. But if you also need extra income, you may think about starting your own business.

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"Entrepreneurship isn't just for brilliant kids eating pizza at 2 a.m.," says Helen Dennis, a specialist in aging and employment. "There's just as much energy and creativity in midlife."

A 2009 "recareering" study done for AARP by the Urban Institute reported that of people who changed their jobs and changed occupations, about 31 percent said they went from working for others to working for themselves.

But working at what?

When you're free to do whatever you want, what do you really want to do? Probably some version of what you did before. And the sooner you get to it, the better.

"A high percentage of retirement businesses take advantage of the knowledge and contacts retirees already have," says Dennis Sargent, coauthor, with his wife, Martha, of Retire — and Start Your Own Business. Martha says that in high tech especially, "contacts are good for about 18 to 24 months."

A smaller percentage of retirees are able to turn their hobby into a business. But the odds are against you if you pursue an entirely new line of work. You might find that it doesn't interest you enough, or that its demands aren't a good fit. Not everyone is cut out to sell real estate on weekends or manage the local coffee shop.

Consulting, starting an errand-running service for seniors, writing family biographies, reviewing building plans for clients, planning parties, acting as a personal secretary for small businesses that don't have assistants, setting up a computer help service — these are a few of the businesses you can start for less than $5,000.

Most retirees want a low-cost, home-based business they can run part time so they can still enjoy their leisure and work with less stress. Finding the right idea, however, takes time. The Sargents suggest you start by writing down lots of ideas, no matter how far-out. Test them against your interests and abilities, then winnow them down. Check aarp.org/work.

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