Ah.... users.

Amusing story of the trouble that can be caused by unbridled downloading of cool screen savers. It turns out the screen saver in question was down loaded by one employee at this law firm who emailed everyone else to tell them about it. The screen saver installed a zombie that allowed the law firm's computers to participate in a bot net executing denial of service attacks against something.

Anyone else have a story to share like this one? Comments welcome. Your identity will be kept secret!