The MIT Mood Meter is designed to assess the mood at key points around the MIT campus, smiles are used as a barometer for happiness and is used to "raise awareness of how our own smiles can positively affect the surrounding environment".
Real-time information is produced and can be used to help answer questions about the mood of students on Campus and is viewable on the project web site MIT Mood Meter.

I really like this concept as it is casting votes through mood and seems to be a very real way to analyse and improve factors around campus that may be preventing good moods.