Eco Vacations

Thought this was interesting...
The Benefits:
*Harmony with the planet. You'll be performing essential work such as coral reef restoration (yes, you can likely squeeze in time for a margarita at the end of the day).
*More cash for cassette tapes. Volunteer vacations are often less expensive than vacations at the usual tourist haunts.
*New waves of skills. Learn how to monitor dolphin migration patterns, farm organically, or restore trails - sometimes stuff you can put to use when you get back home.

Earthwatch Expeditions - work with researchers studying topics such as Kenyan elephant behavior and climate change's effect on the Arctic ($2,350 and up, not including airfare).
Oceanic Society Expeditions and Reef Check EcoExpeditions - scuba dive, snorkel, or boat your way to monitor underwater life in oceans across the globe ($999 and up, not including airfare).
American Hiking Society - spend a week building and maintaining trails across the United States ($275, not including airfare).
Worldwide Opportunities on Organic Farms - more than 1,000 organic farmers offer you food and accommodations, in exchange for your work on their organic farm.
GAP Adventures, Sustainable Travel International, and Travelocity Travel for Good - search for volunteer vacations; tons of options.
The 100 Best Vacations to Enrich Your Life - great book intro to "experiential" travel and volunteer vacations ($14).