Deep in the annals of Nintendo history is a special edition of Donkey Kong, titled the "Original Edition." It included the Cement Factory stage absent from the NES title, and it's never been offered for sale. If you want to get your hands on this rare bit of Nintendo history, you have your chance. You'll need a Club Nintendo account and you'll have to buy a game, first.
A Club Nintendo account (via Tiny Cartridge) is required to get the bonus. If you get an eligible game through a digital purchase on the eShop by January 6, you'll get a download code for Donkey Kong 3-4 weeks after purchase. The titles include Paper Mario: Sticker Star, Professor Layton and the Miracle Mask, Crosswords Plus, Art Academy: Lessons for Everyone, and Style Savvy: Trendsetters. If you were already planning on getting one of those games digitally, score.
Club Nintendo offered an incentive for digital purchases of New Super Mario Bros 2 as well, in the form of double-value on Club Nintendo coins. It seems like this move is another experiment to test how to coax players to purchase games through its online shop, without offering discounts from the brick-and-mortar price.