Kurt Vonnegut was still alive when Larry Niven and Jerry Pournelle consigned him to the sixth circle of Hell, in their 1976 novel Dante-inspired novel Inferno, which just had a follow-up, Escape From Hell.
Blogger Robert R. Chase points our attention to the Vonnegut cameo in Inferno, which takes place during science-fiction author Allen Carpenter's tour of the sixth circle of Dante's Hell:
Green light blinked on and off in the corner of my eye. It was annoying, a disturbance, an irritant in the thick cotton closing about me. I could see the source without turning my head, but it was an effort to move my eyes. Why bother? But the light winked on and off, and eventually I looked at the source, a neon sign blinking far down at the dead end of a corridor of the dead. It echoed my thought:
SO IT GOES
SO IT GOES
SO IT GOES
At the end of the corridor was a tremendous square-cut edifice in black marble. The epitaph beneath the neon sign was long and wordy, couched in words of one syllable and short sentences. A man's life history, a list of books and awards —
Corbett and Benito stared when I came back. Corbett said, "You look like you're ready to kill somebody."
I jerked my thumb behind me. At first I couldn't speak, I was that angry. "Him? Why him? A science-fiction writer who lied about not being a science fiction writer because he got more money that way. He wrote whole novels in baby talk, with sixth-grade drawings in them, and third-grade science, and he knew better. How does he rate a monument that size?"
Benito's smile was lopsided. "You envy him that tomb?"
"If you must know, I was writing better than he ever did before I left high school!"
But it turns out that Vonnegut's huge tomb is due to the fact that he created two fake religions, in his novels.
As Chase puts it:
As in Dante's version, we occasionally hear the sound of personal axes grinding. Kurt Vonnegut may have a tomb complete with blinking neon SO IT GOES sign because he made up false religions, but it is clear that Niven and Pournelle put him in the sixth circle for different reasons.