From Big Download:

Saturday is International Talk Like a Pirate Day, a sort of informal holiday when people say, “arrrr!” a lot. To celebrate the occasion, TellTale Games and LucasArts are letting Guybrush Threepwood, Mighty Pirate lead the way with some awesome deals on Monkey Island games.

Lucasarts is providing steep discounts on its Monkey Island games to celebrate the occasion, with the first episode of their new episodic game Tales of Monkey Island given away for free for a limited time.

This looks like a great way to tie in a game with a rare real-world occurrence (sadly, not too many pirate-related days, anymore) and push users into a string of episodic games by giving away the first one for free.