However, I did see something that might be practical as well as fun. A company called 'FLIR' has announced a "Personal Thermal Imager" for the iPhone.
I can see a number of practical uses; finding insulation leaks, for example. That would be handy in both Sweden and Texas! It would also be fun to spot a moose in the woods, or Ollie in the backyard.
I'm not sure I'll be buying one just yet. The idea that something which used to cost hundreds, if not thousands, of dollars is now just an iPhone accessory is something I really get a kick out of!