Smile to Keep Rio Happy.
SantaClaraNitro out of Sao Paulo, Brazil did this pretty interesting outdoor experiential thing. As you text the answer to the question "Is Rio happy?", the smile on an outdoor increases based on the overall number of calls received. Of course, since I live in a town of about 439 people, no smile would be happening anytime soon. More like, toothless grin.
(+ Enlarge to see how the sequence of events goes.)