Here is the link to the New Yorker Fiction Podcast - so you can listen to this story as well as the even darker story "Game" (which will give you a very good feel of the Cold War era that we talked about so much) and many, many more excellent stories - all for free!
And here is an essay by George Saunders on this story - it is also a great (and again, I find it funny) revision of the structure of a classical short story.
Homework:
“A short story can be thought of as a series of these little gas stations. The main point is to get the reader around the track; that is, to the end of the story. Any other pleasures a story may offer (theme, character, moral uplift) are dependent upon this.”
This is George Saunder's definition of a short story - write down the "gas stations" in Donald Barthelme's story and be prepared to explain your choices.