This wearable headset is from a company called Neurowear. It's supposed to be able to tell when you're excited about something. When it detects interest, presumably from your brain, it turns on your phone's video camera. Of course, you'd have to be a little careful where you wear this thing, but it'd make for a pretty cool little toy to break out at a part or something like that.
The most surprising thing about this device might just be the price. It only costs around $22, which is much cheaper than some of the other items on this list.