WebEcoist's list of "20 Strange and Exotic Endangered Species" is a sad marvel of incredibly odd creatures that your kids might never get a chance to see.
This is not shopped. This is not a hoax. That is a giant crab on a garbage can. They're native to Guam and other Pacific islands. Coconut crabs aren't endangered, per se, but due to tropical habitat destruction they are at risk. In WWII, American soldiers stationed in the Pacific theater wrote home with tales about entire atolls being covered in the armor-plated giants. These crabs can crack a coconut in one swipe; but they're generally too slow to be very dangerous to humans. Children pass lazy afternoons by picking the crabs off tree trunks and watching them crash to the ground; it's reportedly great fun. And kind of messed up.
(Image: Giant coconut crab by Jason Kottke)