Have a look at playing the Asteroids game with a card, it's quite intuitive. I'm not saying we should play all games this way (I like d-pads too), just showing we can, and it's worth exploring.
With Paprika, it's really simple to bind properties like position/rotation of a card and have it trigger an event when you flip it or stack it.
The goal of this framework is to explore the (huge) gap between card- or board games, and videogames, so we can take the best of both worlds. It's hard work to imagine what users can do with new interaction techniques, but the goal is to make videogames which are more fun with paper/card based interaction than d-pads. Or conversely, to find card/board games that are more fun with a computer (i.e. not a simple 3D animation of the battle between two pokemon cards for example).
