I think the book cover design below isn't exactly humourous, however it's clever as it has a wrap around cover that makes the title of the book disappear, which is relevant as the title is 'Don't Judge A Book By Its Cover Only'. However, you can only read 'Don't Judge' and then one the wrap around cover is a list of credits to artists and the people involved in the book.
Although this isn't a book, this poster design is really comical as the statement of the poster is relevant to how the statement is set out. For example, the designer has played with the curning and tracking of the type, making it readable, however not very legible. As a designer, it doesn't exactly piss me off, as I think it is still nicely designed, however it does put me on edge quite a bit. I think the actual layout of the left-alligned type is something I want to take forward into my own book.