On-air brawling between MSNBC's Keith Olbermann and Fox News Channel's Bill O'Reilly dates back to late 2005, but this year the feud between two of cable TV's most watched talking heads escalated to a new level: the corporate parents got involved. At a conference in May, the CEOs of GE (which owns MSNBC) and News Corp. both expressed regret at how vicious and personal the barbs between the two prime-time anchors had grown. Shortly thereafter, a cease-fire was called, with staffers at both networks being told to lay off insulting those at the other. For a while, it worked. But it can be hard to lay down arms after a long-standing battle, especially when that battle is such a ratings booster. By August, O'Reilly was back to slamming GE, implying that the company indirectly supplied materials used to make roadside bombs in Iraq. GE came out in full force, calling such a supposition "irresponsible and maliciously false." The next night, Olbermann was back at it too, naming O'Reilly one of the "worst persons of the world" — as he had done so often in the past.