Sep 19 2007
Talk Like a Pirate Day. Arrr!
This should be the official mascot of the day:

[Link]
In case you were wondering why:
John Baur and Mark Summers, who have come up with a concept that is going to make you kick yourself for not thinking of it first: Talk Like a Pirate Day. As the name suggests, this is a day on which everybody would talk like a pirate. Is that a great idea, or what? There are so many practical benefits that I can’t even begin to list them all.” — Dave Barry, Miami Herald, Sept. 8, 2002.
(from http://www.talklikeapirate.com/ )
And in case you want to join in the fun, here’s a little training vid: