I think my favorite are the fish one and the penguin goal photos. And speaking of animals, this brings up the subject of animal photography. :P
To be honest, I haven't done as much animal photography as I wish I have. (unless you count the random squirrel shots I've taken) I don't own any pets, nor do I take pictures of pets on walks and such, I'm not as familiar with the subjects as I can. However, like a lot of other photography subjects, this especially requires patience. You can have a set shutterspeed and all, but focus can be an issue, since animals act however they want over what you'd want.
But at the same time, that's also the beauty of it. With patience, that perfect shot can come at any moment and it will be worth it!