According to the CIA, "Criminals have been able to hack into computer systems via the Internet and cut power to several cities":

Criminals have launched online attacks that disrupted power equipment in several regions outside of the U.S., he said, without identifying the countries affected. The goal of the attacks was extortion, he said.

"We have information, from multiple regions outside the United States, of cyber intrusions into utilities, followed by extortion demands," he said in a statement posted to the Web on Friday by the conference's organizers, the SANS Institute. "In at least one case, the disruption caused a power outage affecting multiple cities. We do not know who executed these attacks or why, but all involved intrusions through the Internet."

It's almost like living in a real-life Bruce Willis movie.