I watched the 1999 film adaptation of Breakfast of Champions yesterday evening. I decided to check this film – after having read the delightful novel in Spain a week ago – because I considered the novel unfilmable. Unfilmable because of the book’s tone, which hovers perfectly between the surreal and the very mundane. Unfilmable also because it is an illustrated novel (with crude illustrations by Vonnegut himself, the anus illustration at the beginning sets the tone) and because the novel features many matter-of-fact explanations (what is a cow?, what is earth?, etc.).
The film was written and directed by minor American director Alan Rudolph and stars Bruce Willis, Albert Finney, Nick Nolte and Barbara Hershey. The film was widely panned by critics. It is indeed painful to watch.
This  unidentified excerpt – from a Vonnegut documentary I presume – is exactly what I have in mind.
Breakfast of Champions (the novel) is cult fiction item #8.