The Penguin Foundation is an organization that rescues penguins hurt by oil spills, cleaning them and then releasing them back to the wild once they are healthy again. The problem is that they can't clean all of them fast enough and before the penguins get their baths they are susceptible to hypothermia because the oil destroys the natural insulation of their clean feathers.

Also, the penguins don't like the oil so they try to groom themselves which results in them ingesting the crude oil as well as picking themselves bald in the process. To avoid these problems the Penguin Foundation gives them sweaters. To see more pictures of well-dressed sweaters you can read the Buzzfeed article. To make sweaters to donate you can download the pattern. Or you could just send them cash donations.

Update: There is some dissent to this in the bird rescue community. Also, it seems that the foundation sells toy penguins wearing the sweaters as a fundraiser. Thank you commenters for the updated info!