She don't?

These are examples of either standard English for a dialect other than Standard English or they are examples of non-standard Standard English.

English has many different registers. The way English is actually used in REAL life is not the manner described by most grammar books. Yesterday, I watched a video of Senator Joe Biden, [being interviewed by Tim Russert], in which he said,

"There ain't no lockbox. ... There ain't no IOU."

Now, lest anyone think that Joe Biden is an uneducated man, read this;

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Joseph R. Biden, Jr. was first elected to the United States Senate in 1972 at the age of twenty-nine and is recognized as one of the nation’s most powerful and influential voices on foreign relations, terrorism, drug policy, and crime prevention.

Senator Biden grew up in New Castle County, Delaware. He graduated from the University of Delaware in 1965, and from the Syracuse University College of Law in 1968. Prior to his election to the Senate, Biden practiced law in Wilmington, Delaware and served on the New Castle County Council from 1970 to 1972. Since 1991, Biden has been an adjunct professor at the Widener University School of Law, where he teaches a seminar on constitutional law.
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Sometimes well educated people say such things to attract attention, to stress informality, or to joke.
I think most people would agree that it is NOT STANDARD ENGLISH

I have to say I feel a bit embarrassed after having read some of the responses. . . but then again maybe I read wrong. "She don't", as has already been mentioned, is non-Standard English, but allow me to add that it is English, notably a variant of Ebonics or Ebonics itself, a dialect spoken in the USA, and it has rules just like the Standard dialect. In other words, Sextus, it's a dialect. Whether it's indicative of education, socio-economic status, or the quality of one's character, shockingly enough, is pretty much what the speakers of Old English thought about new variants of what was to become Middle English, and in turn, what they thought of what was eventually to become Modern English, or English as we know it today. That's the operative word "we". We are indeed traditionalists, in our own right, when we prefer one system over another. And when we sell those wares, we become prescriptivists.

I can't agree more with you, Casi. Purists may call this speech pattern non-standard English, but all said and done, it is English. All varieties of English, any language for that matter, including this one, have their own set of established standards and are governed by their linguistic and cultural rules which are followed by most speakers of that dialect. This particular dialect of English that's being discussed here is called African-American Vernacular English (AAVE), also called Ebonics in linguistic terms, and black or African-American English in common language. It's believed that AAVE has grammatical origins in, and pronunciational characteristics in common with, various West African languages. Here's a quick peek into its grammar (in no particular order):

1. Uninflected present-tense verbs:
I go, We go, You go, He go (=He goes, in Standard English), She go (=She goes), It go (=It goes), They go
I don't go, We don't go, You don't go, He don't go (=He doesn't go), She don't go (=She doesn't go), It don't go (=It doesn't go), They don't go
2. No -s to indicate possession: My baby mama (=My baby's mama)
3. Double negatives: I didn't go nowhere (=I didn't go nowhere), He don't want to do nothing (=He doesn't want to do anything)
4. Modified Present Continuous form: She talkin' (=She is talking)
5. Modified Present Perfect Continuous form: She bin talkin' to him (=She has been talking to him)

What I've described above is only tip of the iceberg; there's much more to it explaining which would be out of scope of this discussion. An ESL learner would be better off mastering the standard dialect first, and then explore other varieties of English.

Thank you for reading.