Here are links to blog posts, articles, and videos that have a strong impression on me, and have impacted the way I teach (or, at least that way I would like to teach).
Dan Meyer - The Comprehensive Math Assessment Resource
John Burk - What is understanding, and how do you teach it?
Kate Nowak - Keep Learning
Shawn Cornally - Standards-Based Grading: Manifesto
Conrad Wolfram: Teaching kids real math with computers
Dan Meyer: Math class needs a makeover
Ken Robinson says schools kill creativity