The 3DS's Augmented Reality, or AR cards, are quite hard to explain. Using the 3DS's dual 3D cameras, the system detects the card, and then adds other objects, or characters to the screen, effectively turning your desk into a living, breathing game world. An AR card we went hands-on with at a recent Nintendo event in Amsterdam turned your desk into a target range, which you had to physically move around in order to shoot the targets.
Nintendo have recently even gone as far as to say that they hope the AR games will be as popular as Wii Sports. In a recent investor conference, Satoru Iwata, Nintendo's President said "The inclusion of such preinstalled software, the attraction of which can be readily realised by those people even without prior interest in Nintendo 3DS, will hopefully be able to work in a similar way that the bundling of Wii Sports worked for Wii in the US and in Europe." And with the inclusion of a Kirby card, they've already got us sold.
Quite what these cards will do still remains to be seen, but at least we know some of the characters involved now - if each card has its own associated minigame, you can colour us excited. If you could collect, and trade cards that each contained their own minigame, it's easy to see that Nintendo could be onto the next playground sensation. Here's hoping they take this one all the way.