(What is Borrowed Fire?)
Here's Notes from Underground from Project Gutenberg.
For the past year or so I've been obsessed with structure, and in particular with undermining "Freitag's triangle"--i.e., introduction --> conflict --> climax --> falling action --> resolution.* The Underground Man, naturally, hates having any structures forced upon him, including 2+2=4, and rails against such things at length in the first part of the book. And by railing, he does win out in the end--maybe he can't defeat 2+2, but he does wreck the triangle.
The first third of NfU, "Underground," is basically ranting. It has no clear narrative structure, no rising and falling action, only churning emotions, intellectual conundrums, and the constant love / hate, push / pull with the reader. The rest of the novel falls under the heading "A Propos of the Wet Snow," and is a much more conventional, triangle-shaped story. It's a memory from the UM's distant past, and may or may not explain how he came to be how he is now. He of course comes off badly, but possibly more sympathetically, in "Wet Snow." Or not. The more I think about the "Wet Snow" section, the more I wonder about its purpose. And that's what's great about this two-part structure.
I can imagine the responses Dostoevky would have gotten in a typical writing workshop: "The second part's great. It really moves. I can really see these characters and relate to them. Definitely cut the first part, though. You're just spinning your wheels. There's no action." But it's the weird relationship between Part I and Part II, and the narrator's refusal to tell a story until he's good and ready, that makes NfU what it is.
So here's an experiment to try, keeping in mind that your writing workshop may lambaste you. Spend the first third of your story (or novella, for that matter) not telling the story. Let the narrator who's on the verge of telling the story lay out all his or her motives, maybe preview the tale and give it some nice, inaccurate Cliff's Notes. Obviously your narrator has to be crazy enough to engage the reader for the duration of this section. You might think of that high school English teacher you loved to hate, and give that teacher some sort of unresolvable moral obsession--like proving the existence of God in a world that clearly suggests otherwise, or resisting some basic law of nature. Then go ahead and tell the story (or rather, a story) in the second part. Don't worry too much about tying the first part to the second, or, worse, with making the second part explain the first. This isn't a flashback to a traumatic childhood, for instance, that tells us why the narrator is such a monster today. It's more like another view of the narrator, and it shouldn't let him or her off the hook.
*BTW I give Eric Puchner a lot of credit for helping me think about these issues, through his Stanford Continuing Studies course, "Fiction that Breaks the Mold."