The question asked for a short play to read over the Thanksgiving break that's famous enough to be readily available and useful for an AP dramatic lit class -- not what's the greatest play of all time. That's why most of us didn't recommend any O'Neill (most of his best work is four or five acts), Shakespeare (the greatest of course, but, rather demanding and "involved" to say the least for a holiday weekend), Kushner, et al ..... I personally also avoided Brecht, Beckett, Pirandello, Ionesco, Sarte, Genet and others, whose work is often short, but extremely dense in terms of textual analysis, and frankly requires additional reading beyond the text of the play itself in order to write a decent analytical paper.
Works like Glass Menagerie, Death of a Salesman, Streetcar, Our Town, Zoo Story, The Importance of Being Earnest are classics, are short, and don't require any supplemental reading in order to fully appreciate them, which make any of them ideal reading for a holiday weekend. Of course reading a critical essay or two on any of them would be beneficial, but unlike reading, say, Beckett or Brecht or Sarte for the first time, it's not really essential and any reasonably intelligent AP high school student should be able to "get" much of what's important about any of those plays from the text itself.
"What a story........ everything but the bloodhounds snappin' at her rear end." -- Birdie
[http://margochanning.broadwayworld.com/]
"The Devil Be Hittin' Me" -- Whitney