It happened to me last week whilst enjoying my time out. I had just updated the Goodplayer video app and was testing it out, streaming some video from my NAS on my home network. I played a couple of minutes of a couple of videos. The last one I attempted to play was a 1080p mkv, which started off ok, but eventually stuttered and froze, as do all 1080p mkvs on an iPhone in my experience. I stopped the video, but didn't close the app. I just put the phone face down on the armrest of my couch, and surfed the web some on my MacBook. A few minutes later, I picked up the phone, hit the home button and the screen looked very odd. It showed the Goodplayer main screen, but the screen was about 50% of its normal size, and a dark blue color. At first I thought it was some kind of screensaver built into the app. I tapped the screen and it started slowly fading to black, and the menu on the screen shrank even smaller. It reminding me of HAL 9000 getting its memory yanked. Then it just went black. I charged it for an hour just in case and tried rebooting. Nothing. I connected it to my MacBook and fired up iTunes. Nothing. I entered recovery mode, but iTunes wouldn't complete a restore. I entered DFU mode. I edited my host file. I did everything I could find to revive the phone. Nothing worked. I took it to Apple the next morning and they couldn't make it do anything either. They said they thought it might be a fried video chip. That made me wonder about that 1080p video; the last thing I did before the phone died. (I later wrote to Goodplayer and they said it was likely a coincidence, which I agree with in theory, but the timing is suspect.) Apple gave me a brand new retail boxed phone on the spot. So far so good, although the previous one worked flawlessly for nearly 3 weeks straight. It's a very odd feeling to have electronics die without a known cause of death and no autopsy report, especially since I've owned every iphone model since day one and none of them have ever failed completely.