According to Tom Donahue, a CIA official, hackers have recently infiltrated various power grids outside the US, and in at least one instance, caused a power outage in multiple cities. We don't know much else: the when, where, how and who were all left for guessing only. But we know that the attacks were done remotely (through the internet) and that current Supervisory Control and Data Acquisition (SCADA) systems (that, as we understand it, represent many of the world's infrastructural networks, software and databases) are sadly out of date.
At the hacking convention DefCon, security firm Tipping Point gave a presentation outlining various SCADA vulnerabilities, and others in the know are claiming that these vulnerabilities are leading to major electronic extortion of utility companies, to the tune of hundreds of millions of dollars.
Meanwhile, the CIA is questioning whether or not SCADA is the vulnerability in question.
I'm just hoping that said hackers live next door to me, and that therefore my power is safe and sound. [forbes]