Doing good while traveling has been a trend for years, but organizations have long required one or even two weeks' commitment, arguing that it takes time for people to get trained and make a difference. For someone who's never volunteered, that can be a high threshold. But more organizations are discovering that a day of help is better than no help at all. Most U.S. national parks have cleanup days and other volunteer opportunities for which they put out a call often on Facebook for locals and visitors who want to donate four hours. (Also check out volunteer.gov/gov for volunteer projects at national parks and with the U.S. Forest Service, Bureau of Land Management and Fish and Wildlife Service.)
It's not just the Teva-wearing set that's gotten on board: in 2008, Ritz-Carlton launched Give Back Getaways, in which every property has joined with a nearby organization for a social or environmental endeavor. Guests might spend half-days assisting staff and locals as they build facilities for street children in Jakarta or plant endangered indigenous trees in Tenerife, Spain. You can do good in the morning and kick back in the afternoon.