3M recently completed an amazing poster-stunt in Vancouver, Canada. They prepped a bus shelter ad with a 3M product called Scotchshield, a see-through film that you can apply to glass which makes it near bulletproof, and filled the postersite with lots of play money, and 500 real Canadian dollars for good measure.
After that they could just sit back and watch the mayhem.....

As passers by did their best to put the Scotchshield to the test, kicking the glass, taking sledgehammers to the glass and going all sorts of crazy over it, the glass withstood the pressures and did not budge. It did not break, it could not be broken. Shame one can't say the same about the aluminum frame which was breached, at that point security guards called a time-out as that was cheating. Canadian local and national news shows reported on all the crazy attempts to get into the poster for the cash, all in all 3M got a lot of press for their money - remember there was only 500 real dollars in there and a single poster site was rented for only one day.