My hope is that what we are witnessing here is a paradigm shift. At the intersection of problem-based lessons, digital projectors, blogging, and frustration with poor-quality textbooks, is blossoming a new way of bringing mathematical understanding to our kids. We don't need to buy anything new, or anyone's permission...just the structure, and the willingness to be observant and curious, and the humbleness to imagine that there might be a better way. I think this is just the beginning. I think this is going to spread like a fire.Coleen wrote a great reply at Structure of Mathematical Revolutions*, and described 3 stages we've entered: transparency, collaboration and organization, along with a possible evangelism stage, in which we'd be convincing other math teachers how great this all is.
Dan added his thoughts here, comparing Kate to Obama, and after that I couldn't help joining the party.
I hope someone will write a chapter describing this phenomenon for the anthology I'm putting together. The anthology is mostly about learning math outside the classroom, but I think it's vital to find ways to bring the great ideas provided by math circles, centers, festivals, home schoolers, etc, back to the classroom, where most kids are learning math.