Book containing the negative reviews of highly rated books, products, or places.
Book of ridiculous or ridiculously superlative Amazon reviews for everyday things.
Convert the plot of Groundhog Day into a Choose Your Own Adventure novel.
"Don't Read the Comments", a book of YouTube comments.
Convert an old book to use only the 1000 most common English words. (See Thing Explainer, which started with Up Goer Five. "You will not go to space today.")
Not sure what I'm making yet. Some ideas: