I'm a card-carrying member of the Association of Supervision and Curriculum Development (ASCD). Out of various professional groups I've been a part of over the years, this one---more than any other---has provided me with the of source material for growing as an educator. I have a "comprehensive" membership, which is their middle tier. I get copies of Educational Leadership each month and the various updates throughout the year---and I get books hot of the presses, too. Kind of a "Book of the Moment" club.
This moment's title is Checking for Understanding: Formative Assessment Techniques for Your Classroom by Douglas Fisher and Nancy Frey. After scanning it, I would have to say that for the "with it" classroom teacher, there isn't much new territory here. Differentiated instruction, questioning techniques, authentic assessment, are all summarized here. I did like a protocol they included for looking at student work. They also have a fabulous "Checklist for Creating Common Assessments" adapted from work by Linn and Miller (2005). It has the desirable qualities for every kind of item you might use (true/false, matching, performance...) as well as an checklist for the assessment as a whole. The reality is that no teacher is going to be exhaustive with this checklist, but I plan to make a copy to glance at from time to time. It's a good reminder of how to take my goals for student learning and be congruent in terms of my testing.
The teacher who shares an office with me thinks I'm quite the nerd when it comes to staying current with best practices. He jokes about it in a nice way, mind you, and I certainly can't claim that he's saying something that isn't true. :) I do enjoy having time and opportunity to look at the latest publications and see what I can tweak in my repertoire to make things better. ASCD's Book of the Moment is good for prodding my thinking and my work in the classroom.