Bob in the ocean while blue tang and parrotfish flit beneath you. Earthwatch Institute calls this research; we call it fun. Its Bahamian Reef Survey teams marine scientists with (paying) volunteers to monitor the coral by San Salvador, a 5-by-12-mile island where Columbus made his first landfall in the New World. Spend the eight-day trip snorkeling to determine the robustness of corals and sea fans; attending scientist-led lectures on the biology of reefs; and visiting historical sites like late-18th-century Loyalist ruins and monuments to Columbus. Stay at the Gerace Research Centre, a former 1950s U.S. naval base on the north coast. The center is just off the beach, providing easy access to some of the very reefs you'll be "working" to protect. earthwatch.org