Update: Deal over.
Amazon is running a Buy one get one 40% off select Hasbro board games!
No code required, simply add the board games to your cart and the discount will automatically be taken at checkout.
There is no official list of eligible games, so to know if a board game is eligible for this promotion, look right under the price on the product page and see if it shows buy 1, get 1 40% off Hasbro games.
Sample games included in this promo: