Take head that you need to be extremely careful when attempting this prank. Broken glass is no joke (it is a great song, though). Essentially, you smash some glass, roll your friend's car window down and put some of the fake broken glass around the driver's side door and in the seat. If somebody is smart, he or she will recognize that it's fake immediately due to the lack of glass around the edges of the windows. However, the average driver will immediately go into freak-out mode about who the fuck would smashed the window!