Being a Masahiro Sakurai game, Kid Icarus: Uprising has approximately five thousand features. One of those features is the ability to scan special AR cards to make various characters, weapons, enemies, and other things appear and do battle with each other. Those cards are typically given away at Nintendo-related events. Now's your chance to get a whole bunch of them.
Nintendo is giving away sets of more than 400 different Kid Icarus: Uprising cards to owners of the game. New owners (or just those who haven't gotten around to registering it yet) must complete the Club Nintendo registration survey before January 6th to participate. Those who have already registered the game should currently see a new single-question survey in their queue. ("Do you want to win 400 AR cards? y/n")
It's not clear how many winners there will be, but the contest is open to residents of the United States and Canada.
