The great MIT Mood Meter claims to know all your hopes, dreams and fears. Well, perhaps not. But it can count the number of smiles in a given area, giving some kind of indicator of mood expression.
The Mood Meter came about when a team of researchers at the place from whence all awesome things come, MIT's Media Lab, hooked up a camera and screen (or projector) to some nifty facial recognition algorithms that can spot faces and smiles in real time. And, after assuring campus security that they wouldn't be recording any images, they placed the installations in four different locations across MIT's campus.