Even if they are banned in your country, you've probably seen a balisong (butterfly knife) brandished in some movie or other. Such scenes usually show a villain deftly waving such a knife centimeters away from someone's face in threatening manner. If you want to learn how to do that and not get arrested by your local police, the BaliYo from Spyderco could be for you.
This product is essentially a pen shaped like a balisong. Where you'd usually expect a blade is a Fisher Space pen, the writing instrument famously used in space since the 1960s and capable of operating in freezing conditions and even underwater.
With this, instead of doing pen-twirling tricks during classes, you will be (with some practice, of course) able to execute some crazy moves like those movie villains. Spyderco even provides an instructional DVD to get you started out with some tricks. Check out the videos on the official Web site for more details.
(Via Crave Asia)