I was trying to find some examples to tell my own book title joke, but I've found this list of the 30 worst book covers and titles and I'm afraid I'm too shocked now -- and I know that Max already knows at least a couple of these ;-)
The title I remember, from 1981, was "Nailing Jelly To A Tree" by Jerry Willis.
Considering the success of the "Dummies" books, and the copycat "idiots guide", I suspect "Directional Derivatives For Brain-dead [censored]" would be insulting enough to get massive sales.
Seriously however: a series of books for "advanced dummies" or even "moderately ignorant" would be interesting. Instead of assuming no prior knowledge, they'd start with some basic skills assumed [and a reference if the book proves too hard].
The scans of some old "advertisements" that Thomas Payerle developed (with my help) for Random Howe's Book-of-the-Month Club might be of interest even though they do not quite fit this catagory. One has titles such as The Search for Terrestrial Intelligence and Do-It-Yourself Cerebral Repair (with brief descriptions); the other includes titles such as Flying Saucer Cover-up? and The Human Brain: a User's Guide.
(If you enjoy such odd humor, you might also enjoy the other scans [of advertisements for Big Sam's Anatomical Warehouse]. Sadly, some of the other bulletin board flyers we developed while at Washington University have not survived: Nunzio's Mortuary and Pizzeria [with free pick-up and delivery], a notice for a buyer of teeth named T. Faerie, and a notice of a lost Protoceratops [from an institute of temporal studies] are the ones I remember and there were some other [now lost] Big Sam's ads. The artistic quality was not great, but they did provide a few smiles.)