Here’s another blog to keep an eye on:
Recipes for Pi, by Anna Weltman.
I know Anna IRL. In fact, both of us have seen the other one teach. Thus prior to discovering her blog I already knew her as mathematically thought-provoking, endlessly creative, and deeply tuned in to student experience, not to mention a total sweetheart.
So I was excited to learn that she had started blogging in February, and her writing hasn’t disappointed. It’s sporadic, but who am I to complain about that, and more importantly it’s characterized by that same deep thinking about math and student experience that marks her teaching. Check it out.
Aside: Anna teaches at St. Ann’s School, along with Justin Lanier, Paul Salomon, and Paul Lockhart.
Research in Practice 
Not only have I seen you teach, but I’ve been a student of your teaching – in all meanings of that phrase. Thanks, Ben!
Is it too late for me to enroll at St. Ann’s? I’m 43.
@Dan to add to the St Ann’s gushery. Avery Pickford http://www.withoutgeometry.com/ and Dan Finkel http://mathforlove.com/blog/ both taught there as well.