Here at TouchArcade we've been kinda down on iOS hardware gaming accessories. They tend to add bulk and cost and also sacrifice convenience, and I don't think the BowBlade changes any of that.
For $185, the BowBlade is an iPhone Bow and Arrow type accessory that was being shown at Macworld 2013. The iPhone goes in the front, you extend the bow and use a small trigger with your back hand to fire. The company reports over 35 games have support for the device and we shot a short video showing how it works:
The games use a combination of accelerometer and positioning in combination with the triggering system (which taps the screen in a certain location) to provide the overall gaming experience.
One of the sample games was an Augmented Reality type view of the real world in which you could shoot virtual bullets with the trigger. The more fleshed out games include a sniper-type one where you must move around in real space to find your targets, and a duck hunt type game (as seen in the video).
The device will go on sale on April 1st (seriously) for $185.