why we're worth hanging out with... things we do together...
below are some things that have cropped up organically through people who blogged and tweeted. click around and see some great stuff!
Every week, a group of math teachers will meet online and spend an hour or so discussing a given topic.

A small collective of math teachers contribute regularly and sporadically to this group blog  archive small moments of good in sometimes sublimely wonderful and sometimes horrifically sucky days teaching.

A site which has sets of four objects, all of which are unique in some way. These puzzles (for all different grades) get kids thinking, talking, and using math vocabulary!

VisualPatterns is a site created by one of us, but contributed to by many of us, with (obvi) compelling visual patterns to generate math discussions at all levels

"Fraction Talks are a built around classroom talk and student action... I project an image, choose a section to be shaded, and ask students, “What fraction is shaded?”. Students develop an answer (and reasoning) individually, and signal to me when they are done (usually with a thumbs up). I then extend invitations to share."

#TwitterMathCamp, a conference held for us, by us

teacher.desmos.com
As the tagline says, "Handcrafted classroom activities. Designed by teachers. Built with love by Desmos." 
A site created by a tweep/blogger which asks scaffolded estimation questions  one a day, and they build off of each other.

A (free!) ebook which catalogs many of the tricks ("cross multiply!") that teachers use to teach, and provides conceptually sound alternatives... This book was created by crowdsourcing the mathtwitterblogosphere.

Daily Desmos has you (or your students) try to work backwards. Given the graph, what might be the equation? Blogotwitterpeeps make submissions for various graphs!

Infinite Tangents is a podcast about math teaching and learning released every week, put together by one of us. Each week we have NPR quality interviews with math teachers or learn some math teaching news!

Would You Rather is a set of questions where students will be forced to think deeply about two options and articulate reasoning to make an informed decision.

A site crowdsourced with many problems which have an "open middle" (meaning all problems start out the same, all problems end with the same answer, but there are multiple ways to approach and ultimately solve the problem).

Letters to a First Year Teacher, a compilation of 20something letters to newbie teachers

A set of virtual filing cabinets which curate the best ideas from blogs by topic
(others here, here, and here) 
A blog devoted to improving assessments for our students. Teachers submit assessments, teachers give comments on these assessments.

MathArguments180 has an extensive series of discussionprovoking questions for teachers to use in their classrooms.

#Made4Math Mondays, an ongoing series of crafty projects that can improve the math classroom... published every monday by tons of teachers!

Dan Meyer's 101Questions database, and 3 Act Lessons (collaborative work of many people)... More 3 Act Lessons are updated and archived here and here.

#matheme is a math theme that arises spontaneously on blogs (e.g. writing in math classrooms). These are archived.

Collaborative Mathematics and the Video Challenge Project aim to use video as a means of connecting a worldwide community of mathematical problem solvers. The intended audience for this site is primarily middle and high school mathematics students.

A blog where teachers analyze student mistakes in the comments, to better understand student thinking, and how to remediate it. The mistakes are submitted by teachers too.

Compile and archive our best stuff on wikis, for access later. There is the Math Teacher Wiki and the Standards Based Grading Wiki.

A website created by two new teachers crowdsourcing the big and small teaching questions, from core values, to what to do when a kid talks back to you, to how to pass out papers.

Math Munch, a blog written weekly by three bloggers for students and teachers. It curates the most interesting math things out there.

Real math teachers create two minute video blurbs about "How I Teach (whatever)" to share with the world! Mathagogy!

A survey on how we "do" homework in our classes, in an ontheground level.

A New Bloggers Initiation  a month long initiative to get teachers who want to try blogging to do it, with guidance and writing prompts

A site where people submit comprehensive and readable recaps of math ed talks that they went to.

A site of Dan Meyeresque graphing stories, with videos submitted by math teachers all over, and made professional by Dan Meyer and BuzzMath

ActivePrompt is a site created by one of us to satisfy a demand for students to estimate answers first (visually). Its awesomeness is hard to describe  read some blogposts here and here.

A competition where teachers submit videos to teach students a boooring topic (the binomial expansion) while keeping kids engaged. The winning video is above.

Taking really crappy textbook problems and finding ways to revise the problems and the teaching of the problems so you have something amazeballs.

A virtual conference held on Soft Skills was held. Additionally, a year later, a virtual conference on Core Values was held.

Do what you were trying to do in the math classroom blow up in flames? That happens to all of us, and Productive Struggle is a place where people submit their missteps, ask questions, and through reflection, hopefully come out the better for it.

The MTT2K contest sponsored by Dan Meyer and Justin Reich for critiquing Khan Academy Videos.

In one week in November, math teachers around the country archived what one day in their lives looked like  the good, the bad, the ugly.

continually think about the things that you care about, with people that care too. 
write collaborative letters of rec

give ideas for a lesson plan

share all the curricular materials we have...
