Knott's is open 364 days a year, the only closed day is Christmas.
Their Scary Farm Halloween Haunt event (which is a seperate ticket event at night) runs generally Thursday-Sunday nights in October.
Takis advertisement currently resides in the station of and on Boomerang, I hope it doesn't make its way to IRat.
What you don't want to hear this song while you're in a 2 hour line?