Why just one? How about a whole calendar year full of PLA holidays, such as RBCP's birthday, the anniversary of the first call to Dino, February 15, 1990--the date of the first PLA issue... etc.
We could even have our own Christmas-type holiday, where we hang replicas of Tannest's boobs from a tree and wait for Old Saint Chris Tompkinson to come through the phone line and leave us tone dialers in our stockings.