Our little Catholic school is switching to the Four Blocks/Big Blocks model, and my 7th/8th grade classroom is painfully short of books for guided reading, especially in terms of 'easier' books that will hold the interest of teen age boys. Would appreciate any suggestions.

Will you explain the model and let us know the approximate reading level? 

Chris Crutcher books are usually good, esp. for the boys, but you may want to double-check the specific topics addressed in each book since I know some of his books have topics that some parents may find objectionable (though I personally disagree, I know what those parent calls/emails can be like).

Will Weaver is a lesser known author that's a good option.  His kids books are targeted at that level; most popular are his baseball themed triology.  I also liked Memory Boy.  When I checked this site, his books were available for order.  :)

I chatted with a friend of mine who teaches middle school Language Arts (I teach high school English).  She has had success with the following:

Divergent by Veronica Roth

Fablehaven series by Brandon Mull

Among the Hidden series by Margaret Peterson Haddix 

Authors: James Patterson, Gary Paulson, Walter Dean Myers, Jerry Spinelli,

Good luck!

I teach HS but have two boys that are 4th and 7th and they are both non-stop readers:

The Hunger Games trilogy 4th grade -  adult can read and enjoy

Harry Potter series

Among the Hidden series

Diary of a Wimpy kid series

Hatchet or anything Gary Paulson

Charlie Bone series

Mickelson is an author that boys like.  Be careful of the Paulsen books for a Catholic school.  Several of them have language your school would find inappropriate.