Professional skier Nicolas Vuignier has done an experiment in which he whips his iPhone around his head on a string. As he does so, he films the process. As the process unfolds, slow-motion video captures Vuignier in what's commonly referred to as Bullet Motion. Think The Matrix. Remember Neo. The action you're about to see is going to blow your mind, if only because it's been done so simply.
Vuignier has not yet released a "DIY instructions" video, but the process isn't all that difficult.
All you'll need to do is secure your iPhone in a way that will allow it to fly off of a mountain without being damaged. Once you've done this, all you need is string.
The slow-motion effect is achieved in the standard iOS/iPhone camera app, and the result is fabulous.
We'd be waiting for the accessory to make this action more plausible for the common user but, really - what's left? An easier way to attach the string to an iPhone case? Let's see you make it, accessory manufacturers - we dare you!