Whats on the last page of the book? If it is blank, you could take a sheet of paper (or a fancy 'endpaper') and essentially fold it in half, cut it to size, and glue it to both the cover and the last page of the book.
Might look kind of awkward though. If its too thin, it will tear, but if its think, it will stick out... but its something I suppose.
This is basically what is done when you cover a hardbound book. If you look at the endpaper, it is just glued to the hardcover and to the last page of the book.
On that note, there is specific glue used for book binding that might adhere better to the ripped cover and what remains of your book.
Last suggestion, buy a new one? I just got a gently used hardcover of CoD for $6 on ebay. You would probably be able to find one in slightly better condition than yours currently is for cheaper than the glue you might have to buy, even if its only like $2.
This post has been edited by Wilshire: 23 December 2014 - 01:06 AM