To hype today's release of Thomas Pynchon's Inherent Vice, Penguin Press has released this book trailer, unenthusiastically narrated by a person assuming the guise of Doc Sportello, the novel's Big Lebowski–ish protagonist. Since it's certainly not Don LaFontaine's, speculation is the voice could belong to the famously reclusive Pynchon himself. GalleyCat asked Penguin for clarification, but they replied with "No comment." Having only Pynchon's 2004 Simpsons cameo (embedded after the jump) to compare it with, this totally sounds like it might possibly be him, maybe.
Here's Pynchon's Simpsons cameo: