This piece from Back of the Cereal Box, while comical, does bring home the concept of how profound a change simple punctuation can make. From the post:

My question was quickly answered by her response, “Who you are? Why you come here?”

Interestingly, the article itself contains punctuation errors:
Upon speaking with various members of the proofing department at length about the question mark erroneously affixed to the end of the film’s title on various posters, press packets, TV commercials, certain versions of the trailer, and all incarnations of the various Where the Wild Things Are video games. I eventually arrived at Ms. Anoldi’s office — which exists in a room that I previously thought was only used to store old furniture — and asked her if she was, in fact, the person who inserted this punctuation mark.

Did you see it? That fragment right there? Instead of a period, Drew obviously intended to continue the thought of the sentence, necessitating a comma.

Also of note, a spelling error:
She eventually chased me away by repeatedly rapping me on the head with a wooden spoon that she had been using to stir a pot of what appeared to be marina sauce.

Has anyone out there ever heard of this alleged "marina" sauce?

Source: http://kidicarus222.blogspot.com/2009/09/but-truly-where-are-these-wild-things.html