1. Coral Reef Survey, San Salvador Island, Bahamas
Help save coral reefs simply by snorkeling. Well, you do have to measure and map as you splash along. Three U.S. researchers have been studying the reefs for years with help from the Earthwatch Institute, a nonprofit organization that gives ordinary people a chance to assist in scientific projects. A session in the Bahamas (June 29-July 9 or November 19-26), including food and lodging, costs $1,830; 800/776-0188 or earthwatch.org.
2. Whale Watching/Photography, Petersburg, Alaska
Choose Jodi Shepherd-led safaris, which offer plenty of general nature-photography tips, or Jim Nahmens' "Blubber Lovers" adventures, which focus more intently on humpback whales, especially their feeding behaviors. Either way, Alaska Sea Adventures' small-ship (only eight passengers) cruises follow ethical viewing guidelines for all wildlife. Inside Passage scenery alone makes this a photographer's dream vacation. Trips are scheduled for June and July; 888/772-8588 or yachtalaska.com.
3. Boatbuilding, Brooklin, Maine
At WoodenBoat School, you can create your own boat in a week―and maybe even take it home with you. Or, if that seems a bit ambitious, you could warm up by building a pond yacht (a working model sailboat). Other course topics include decorative carving, watercolor painting, and diesel-engine repair. The schedule runs May through September; 207/359-4651 or thewoodenboatschool.com.
4. Canoeing the Everglades, Ten Thousand Islands, Florida
Less than an hour south of chic Naples on Florida's Gulf Coast, the world gets wild. In this edge-of-the-Everglades ecosystem, land and sea mix as they do nowhere else in the country. Thousands of tiny islands create a lacework of bays and channels. Mysterious streams under tunnels of arching mangroves lead to flocks of herons, egrets, and roseate spoonbills. Wilderness Inquiry leads a canoe/camping trip through this ecosystem, heeding its mission to make the outdoors accessible to everyone―including people with disabilities. Next dates are in February and March 2006; 800/728-0719 or wildernessinquiry.org.
5. Weed Removal, Point Reyes, California
This Sierra Club outing involves yanking out non-native plants that have invaded Point Reyes National Seashore, the stunningly scenic Northern California preserve. You'll learn about the area's abundant wildlife and see evidence of the 1906 earthquake that devastated San Francisco, 35 miles south. May's trip is booked, but September 11-17 is available; 415/977-5522 or sierraclub.org/outings.
6. Cooking Classes, The Waring House, Picton, Ontario, Canada
Choose from all manner of classes covering everything from knife-sharpening to French bistro cuisine. Classes, workshops, and special education/accommodations packages carry on year-round. The 17-room Waring House inn and restaurant sits in the middle of a charming Lake Ontario town; 800/621-4956 or waringhouse.com.
7. Ecosystem Preservation, Kauai, Hawaii
Global Volunteers, founded in 1984, sends adventurers on service-oriented visits to rural communities around the world, with full immersion into the local culture. This project, on Hawaii's "Garden Island," seeks to preserve native Hawaiian plants. You might uproot non-native species, repair historic buildings in a state park, or even help put on a festival; 800/487-1074 or globalvolunteers.org.
8. Historical Cruise, Chesapeake Bay
Smithsonian Journeys, affiliated with Washington's Smithsonian Institution, has put together a nine-day educational expedition through places that shaped the earliest history of the United States. The trip aboard the cozy, 49-passenger American Eagle starts and ends in Baltimore. Stops include the archaeological site of St. Mary's City, Maryland's now-vanished first capital, and lovely St. Michaels, Maryland, a wonderful town for history, seafood, and antiques; 877/338-8687 or smithsonianjourneys.org/cruises_us/042005chesapeake.asp.
9. Delta Exploration, Skagit River, Washington
The North Cascades Institute, headquartered just north of Seattle, aims to "inspire close relationships with nature through direct experience in the natural world." In other words, you get taken to beautiful places and find out what makes them so amazing. In August and again in January 2006, biologists will guide weekend trips through the huge variety of plants and animals in the Skagit River delta. They'll also point out successful conservation projects by local landowners; 360/856-5700, ext. 209, or ncascades.org.
10. Sea Turtle Conservation, Wassaw Island, Georgia
Throughout the summer, the Caretta Research Project brings everyone from schoolchildren to senior citizens to an uninhabited barrier island southeast of Savannah. There you help protect nesting sea turtles, their eggs, and their hatchlings. ( Caretta caretta is the scientific name for the loggerhead turtle.) You'll stay in primitive cabins and assist with housekeeping and cooking. Expect an extremely rustic but intensely rewarding experience; 912/447-8655 or carettaresearchproject.org.