FLIR One

It's actually pretty useful for weatherproofing a house; we used to use pretty expensive thermal imagers to check for leaks in the winter.

I was thinking the same thing as @drizzled (via his TC article - http://techcrunch.com/2014/01/07...): "At first, I was a little skeptical about the potential use cases for a thermal iPhone case for the average consumer, but the company’s representative at CES explained that you could use it for something as simple as figuring out whether your dog is climbing up onto your bed when you leave or not. It could also be used for home security, detecting thermal leaks in your house, or finding water leaks in pipes behind the walls."

want!