I like this concept from fiftyfifty a German homelessness charity.
It's a cinema ad, shown in a cinema where the air conditioning was set low to demonstrate the reality of being cold and homeless.
Really clever, great for press coverage, but I think it would have raised more money with an SMS call to action.
QR codes aren't a campaign, they are a method of response. Every phone has SMS built in, SMS is frictionless. See it, feel moved, respond in seconds. QR codes are only spontaneous if you have a reader on your phone - no phone I have ever had has one preloaded.
But I still love the idea.
Found on this great QR Code resource site.