This is one of the coolest things I’ve seen in a long time. Bryce Bell over at Cardnetics is making a business out of creating cards that also turn into little toys and gadgets. He’s currently producing one card and has a 2nd one as a prototype.
The Cardapult
The Penny Shooter
Just be careful that you don’t accidentally cause your school, work, airport terminal, or church to be locked down with your new toy/weapon.