I'd like to second the recommendation for "genre" months rather than specific
sources of books such as "MR". Obvious genres would be:
Crime and Mystery
Horror
Adventure
Horror
Humour
Romance
SF/Fantasy
Biography/Autobiography
Classics
It should be pretty easy to extend this to cover 12 months, if that should be deemed appropriate.
EDIT: I'm not suggesting that "Horror" should really be in there twice
. I don't like horror books, personally!