Edge of the Financial Cliff
StuxNet is a virus that allows the complete covert takeover of a computer system. It was used in Iran to disrupt the nuclear weapon development program, and is estimated to be on many, many computer systems throughout the world. It is not clear who created the virus, or how, or for what purpose it exists. Cryptographers at the FBI and NSA found the worm and utilized it for their own purposes in Iran, but the source is still unknown. Here is a 20-minute lecture on StuxNet, what it does, and why it is dangerous: