Alright. Wikipedia has this one slightly wrong, I believe. The backstory, quickly: a man once assaulted Dan Rather shouting, “What’s the frequency, Kenneth?” or, according to Rather, “Kenneth, what is the frequency?”
Now, the wiki just says that the assailant, William Tager, thought news stations were beaming things into his head and he wanted to know what the hell the frequency was so he could stop it. This is not quite what I heard, a long time ago, from a very good source.
The longer story goes like this, and is more interesting: Tager believed he was from an alternate universe, sent to our universe by the Vice President in his — and in his universe, Dan Rather, who is actually named Kenneth (they all have doubles with different names) and who is the Vice President, authorized the action to send him over into our universe. Why Tager thinks he was sent is unclear. What was clear was that he didn’t know how the hell to get back. Kenneth, or Dan Rather, was supposed to provide him with the proper “frequency” to reach his home universe/dimension and get himself out of this mess. But he never got the frequency. So, logically, he went after Dan Rather, believing him to be Kenneth from his universe, and demanded the frequency to get back home.
I know. Why do I bother remembering stuff like this, right?
Cuz it’s fun!
And that, my friends, is what I’ve heard of the story of “What’s the frequency, Kenneth” (or “Kenneth, what is the frequency?”) and I’m too damn lazy and not sure enough of myself to edit the Wikipedia, but if someone gets the urge to look up the facts on my version, please, go ahead and edit the Wikipedia.