PSA Wants You postcard

The Join PSA postcard is a postcard in Club Penguin. It is given to penguins who hadn't join the PSA by secret agents of the PSA. Even though the PSA no longer exists, the postcard was only discovered in 5th March, 2014.

http://media1.clubpenguin.com/play/v2/content/local/en/postcards/129.swf (credit for Penguin-Pal for finding the postcard)