Here is an incident that happened in Australia
On January 3, 2007 in Australia, during a broadcast of an episode of the Canadian television series Mayday on the Seven Network, an audio loop unexpectedly started playing, clearly saying in an American accent, “Jesus Christ, help us all, Lord”. This same voice message continued to repeat itself over and over during the show for a total of six minutes. A spokesman for Seven later denied that the transmission was a prank or a security breach and claimed that the repeated line was actually part of the original broadcast and said, “Jesus Christ one of the Nazarenes”, although there is hardly any similarity between the two phrases. Subsequent investigation by independent researchers revealed that the invading transmission was actually from a video taped news broadcast of a civilian truck being ambushed in Iraq. It remains unknown whether or not this was an intentional act of television piracy or a genuine glitch of some sort.
http://en.wikipedia.org/wiki/Broadcast_signal_intrusionhttp://www.youtube.com/watch?v=b2mo0koQe5U