Artificial intelligence is pretty neat. Computers, thinking like humans, to help humans do less thinking.
Take Microsoft's Project Oxford - a piece of emotion recognition software that could help robots of the future read the faces of their human masters and determine if they are happy, bored, or terrified that they created a race of super smart robots.
While we still wait with nervous trepidation for that day, we can have a good laugh with the Project Oxford emotion demo page, that'll read the emotions of any photo you plug into it.
Upload a photo - either stored on your computer or via a URL (you can find this on your Facebook images by right clicking an image and selecting 'Copy image URL') - hover your mouse over the blue square that indicates a face and read off the emotions...