Texts From Jane Eyre, by Mallory Ortberg, was yet another coincidental find. This isn't a book, per se - it does exactly what the title says. It presents texts from various characters from famous literature. One of the very best examples is Medea's texts to Jason's new wife ("it's Glauce right?? that is such a pretty name I am so crazy about how pretty your name is 'Jason and Glauce' sounds so good together").
Ortberg runs the gamut of fictional characters, from Gilgamesh to The Hunger Games. It's sort of like a collection of short stories, in that there are some amazing ones (Achilles!) and some good ones (Gone With The Wind) and some eh ones (Agatha Christie). I can easily say, however, that the amazing ones make up for the eh ones. I must have read the Achilles, Medea, and Coleridge texts at least ten times each, and almost cried over them every time.
It's pretty modern humor, and the method of humor doesn't really change - the syntax of what makes the first few texts funny is pretty much what makes all of the others funny, so if you want your favorite authors' voices over-adapted into humor, this probably isn't your book (except for maybe "The Love Song of J. Alfred Prufrock"). But the method works, really really well. Especially if you're in-tune with the kind of passive-aggressive humor that Tumblr specializes in.
Get it from the library. I dare you to read Achilles's text in public and keep a straight or at least an un-embarrassing face.