Back in 2012 when Horse_ebooks was a thing on Twitter, I came up with my own version of it: Xydexx_ebooks. It's an account with titles of books that don't exist, but should. The account was last updated in 2013, but I realized with such great titles as Benjamin Franklin Undressed and The Eel Drinking Game these are books that probably do need to exist.
I'm thinking of making an actual project of it: Create these e-books and post them online. There's also going to be a mail art tie-in: I'm actually creating the books, and that means actually writing the books, and the covers of the books will end up as postcards.
They don't need to be particularly good or make sense, they just need to exist.