Back in January at CES, one of the most magical things we got to see was these new cards from Nukotoys, physical collectible cards that somehow interacted with Apple's capacitive touchscreens (probably with an invisible pattern, if I had to hazard a guess). The project seemed very cool, and Nukotoys told us that it hoped to release by year's end. They're ahead of schedule apparently, because the apps are now available on the App Store, and I'm told that the physical cards are out at retailers available to buy right now.
That link above goes to the Monsterology-branded app, and there'