CHICAGO — Mike Wood spent his recent vacation in rural Honduras, visiting Mayan ruins but mostly building latrines and pig pens.

That isn't exactly most people's idea of a glorious week in the sun. But it was thoroughly enjoyable for the assistant high school principal — and he apparently has growing company.

"It's fun to see how 80 or 90 percent of the people live in this world and try to help them out," said the Deer Isle, Maine, resident, who was on a trip organized by the group Sustainable Harvest Inter- national.

More Americans are starting to feel the same way about vacations with a charitable or humanitarian purpose, where they can build housing or schools, collect field data or work at a refugee camp, orphanage or archaeological dig.

While the trend is hard to quantify, a wide variety of environmental, medical, nature, children's and other groups as well as churches report that participation in volunteer vacations is on the rise.

Surveys conducted recently by CheapTickets.com, Travelocity and the Travel Industry Association of America confirm that consumers are becoming more interested in vacations with a voluntarism aspect, also known as "voluntourism."

Opportunities that once existed largely with nonprofit activist groups are being adopted by a wide range of travel agencies and tour operators, too. Sally Brown, who heads the Indianapolis not-for-profit group Ambassadors for Children, said the number of travel organizations of various kinds that offer voluntourism trips has probably doubled in the past three years.

Like the 55-year-old Wood, many of the vacation volunteers are baby boomers, who have the money to spend and the time to donate as they edge closer to retirement. But with inspiration coming from a variety of sources — be it 9/11, Hurricane Katrina or just having more disposable income — participants range from teenagers to retirees. Voluntourism is catching on in college campuses, where many students would rather spend spring break doing something altruistic than carousing.

They don't always have to rough it, either. Ambassadors for Children even offers a "light" mission in which travelers stay at a four-star hotel in Puerto Vallarta, Mexico, and spend three of the eight days visiting an orphanage, library and preschool. That may appeal to a family group wishing to make a cultural connection, Brown said, or just those wanting to mix purpose with pleasure.

"Immersion with voluntourism is so much more than you could get by sitting on a beach or on a tour bus," said Brown, a one-time flight attendant who founded the organization in 1998.

Wood, who also is a history teacher, didn't spend much time seeing historic sites on his February trip with Sustainable Harvest International. Founded by former Peace Corps volunteer Florence Reed, the organization addresses the tropical deforestation crisis by providing farmers with sustainable alternatives to slash-and-burn agriculture.