from wikipedia: Vonnegut played himself in a cameo in 1986's Back to School, in which he is hired by Rodney Dangerfield's Thornton Melon to write a paper on the topic of the novels of Kurt Vonnegut. Recognizing the work as not Melon's own, Professor Turner tells him, "Whoever did write this doesn't know the first thing about Kurt Vonnegut."
"Dad, why don't you join me on a little reality break, OK?"
"Just 'cause you're in love with Dr. Turner does not mean you're gonna pass her course."
"You got a major paper coming up on Kurt Vonnegut."
"You haven't even read any of the books."
"I tried."
"I don't understand a word of it."
"So, how you gonna write the paper, then?"
"Hi, I'm Kurt Vonnegut. I'm looking for Thornton Melon."
"Want to come in? Dad?"