Players going online with Animal Crossing: Wild World with the downloads option turned on (as it is by default) are receiving a special item from Nintendo today, attached to the following message:
I hope you are enjoying your Nintendo DS. Please accept this New Year's gift with my gratitude.
From S. Iwata
The item in question is a Super Mario Bros. coin, previously found by homebrewers. Nook will buy the coin for 256 bells, and it doesn't appear in the game's catalog for reordering. It's not quite downloadable content as such, but it's a nice plus for game owners nonetheless.