Cory at Boing Boing points to a post about an ice cream machine that determines the amount dispensed based on the stress levels detected in your voice.
Employing voice stress analysis of the user’s answers to specific questions, varying degrees of unhappiness are measured and the counteractive quantity of ice cream is dispensed: The more unhappy you are, the more ice cream you need.
If we had one around our building, I know some people who would be buried in the stuff. :-)