This is one of the coolest videos that I've seen in a long time. It's a guy that uses his finger to break the back window of a car. You have to see it to believe it.
There is some cool science going on here. I am pretty sure that part of it is the fact that he's using fireman gloves, which should transfer a lot more energy to the window during each tap, instead of allowing most of it to reflect back during the bounce. Beyond that, I'm not too sure what's going on in the internal structure of the window.