Local post office had a humungous banner strung across the roofline. It read:
“Have a POSitive experience!”
I believe this is a play on “post office…service?” “Point of sale?”
All I can think of is POS as an acronym for “Piece Of Shit.”
That banner wasn’t up for much more than a week. 
I have a CD by Michael Crawford which is called “The Phantom Unmasked” (it’s currently for sale as “With Love”). On the side of the jewel case, the title reads “The Phantom Unmaksed”. How do you miss a thing like that?
A few years ago, here in Wisconsin, our governor was given line-item veto power. Our governor was Tommy Thompson (now HHS Sec.).
The first time Tommy used his line-item veto, the local paper had a story on it and a picture of him crossing out a line. The headline?
“Thompson’s Penis Mightier Than Sword”
They missed the space between “pen” and “is”. That is one I’ll never forget.
Not actually an in print source, but for our school’s ID cards they misspelt “Mathematics” from California Academy of Mathematics and Science. They left out the ‘e’ making it: “Mathmatics” The administration didn’t realize the mistake until after they started distributing the cards. They took them all back and had them redone.
Painted on the streets at intersection near the grammar school I grew up near, were the words “SLOW SCHOOL”.
Now, that’s kind of funny in it’s own right, but one of the intersections had it as “SLO SCHOOL”