For the Rescue the Reef program. You get lots of stuff for $50 bucks an acre (including a subscription to the Nature Conservancy).

If aren't already aware, the world's coral reefs are in danger of becoming a thing of the past (exaggeration? --no). Rising temps cause coral bleaching, and since reefs are an important ecosystem, all the other animals that depend on it will die also. Input "coral bleaching" into the search engine and take a look.

Again, great idea for gifts or kids and adults.