It is nice to see that Desmos is not sitting on their laurels. You might have seen me mention some of the work that @mathycathy & @mjfenton did when they made some. But now Desmos has created their Activity Builder making it possible to to create your own interactive activities that students can then access via your teacher account at teacher.desmos.com on student.desmos.com. Thanks to @marybourassa for this one.

Need a place for quality activities to help you teach math? Look no further than the newly created repository of activities arising from the MTBoS.This was the products of a session run by @marybourassa and @alexoverwijk of this year's Twitter Math Camp. On this site, anyone who has created an activity can post it using this link http://bit.ly/MTBoSactivity But to see all of the activities submitted so far, use the link below. http://bit.ly/MTBoSbank

Here is a neat little way to make transformations of functions tactile. Use pipe cleaners
Curriculum Tags: MPM2D, MCR3U, MBF3C, MCF3M, MHF4U https://www.youtube.com/watch?v=a7HRlcz-jtM

How many chess games are there? Well we can't tell exactly but there are a lot. Numberphile has tried to quantify the number and in the process touch on topics like patterning, powers and exponents and combinatorics. So check it out
Curriculum Tags: Gr7, Gr8, MPM1D, MFM1P, MDM4U https://www.youtube.com/watch?v=Km024eldY1A

I have posted this in May when I did it but the "official" video has come out. This is my Ignite talk from this year's OAME on fun things about Pi. You can get my actual slideshow at http://bit.ly/petro-ignite-2015 which will have all the related links. And then don't forget to check out everyone else's video at the link below. That is, Amy Lin, Alex Overwijk, Matthew Oldridge, Kyle Pearce, Ron Lancaster, Marian Small, Dan Meyer, Jonathon So, Mary Bourassa, Nora Newcombe, George Hart, Don Fraser, and Sunil Singh. Thanks to @AmyLin1962 for posting these
Curriculum Tags: All https://www.youtube.com/playlist?list=PLYmB4P-NnvCMmrVoREJIszXka8O_AZmC1

I always like the idea of basing what we teach on research. Consider this scenario:

"Jack takes a coin from his pocket and decides that he will flip it 4 times in a row, writing down
the outcome of each flip on a scrap of paper. After he is done flipping, he will look at the flips
that immediately followed an outcome of heads, and compute the relative frequency of heads on
those flips. Because the coin is fair, Jack of course expects this conditional relative frequency to be
equal to the probability of flipping a heads: 0.5. Shockingly, Jack is wrong."

As it turns out the reality is that there is only a 40% chance of getting heads. Read about the research here and try the experiment on your own in your class. Though you could relate the idea of flipping coins could be done in the earlier grades the context here is about conditional probability so it probably works best in Grade 12 Data Management
Curriculum Tags:MDM4U http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2627354

Though it has been around for a while, I just stumbled across it. The Poetry with Mathematics blog does, just that. Intersects poetry and mathematics in both fun and serious ways. Check out their offerings here:
Curriculum Tags: All http://poetrywithmathematics.blogspot.ca/

Here is a loaded question: Is Math Important? This is what these 5 panelists discussing over the course of an hour or so. They make their case for (and against?). I was hooked as soon as I heard Steven Strogatz started with takedowns (kind of) of the standard reasons to say "Yes". Take some time to watch and listen. Thanks to @profkeithdevlin for this
Curriculum Tags: All http://video.pbs.org/video/2365521689/

I love cool uses of data. Here is a dynamic visualization of sunset/sunrises created realtime from scraping Instagram for images tagged with #sunset or #sunrise and then mapping them onto the globe. Check out the link below to see the dynamic visualization.
Curriculum Tags: MDM4U http://www.washingtonpost.com/blogs/wonkblog/wp/2015/06/29

I really like this very simple tweak to questioning that @k8nowak has on a recent post. She was having trouble with students not answering questions about other student's work. She got around it by changing the question she asked to "would you explain your understanding of Bianca's Solution?" I like it because it is a little more friendly than "Does anyone have any questions about Bianca's Solution?"
Curriculum Tags: All http://function-of-time.blogspot.ca/2015/07/a-magical-incantation.html

The Nardo Ring is a circular test track in Italy and here is a 3Act task on a problem about two cars driving around in it. Certainly any class dealing with circumference and rates could make use of this.
Curriculum Tags: Gr8, MPM1D, MFM1P http://whenmathhappens.com/2015/07/08/nardo-ring/

It's summer time so why not have a mathematical parody about factoring quadratics. Thanks to @k8nowak for this one
Curriculum Tags: MPM2D, MFM2P, MCF3M, MBF3C, MCR3U https://www.youtube.com/watch?v=DhSjD5nLkjY

When ever I see a fountain I see a quadratic. This time, at the corner of Queen and University in Toronto, it was a great paraboloid.
Curriculum Tags: MPM2D, MFM2P, MCR3U, MBF3C, MCF3M https://twitter.com/davidpetro314/status/621116745428901888

You might have seen these memes on the Internet about never needing to use algebra, well here is a nice little post about why you need it every day.
Curriculum Tags: All http://www.fromquarkstoquasars.com/use-algebra-time/

Recently it was Tau Day (June 28th) and Vi Hart has created a (sort of) new video in homage to it. She has been doing a lot of work with this 360 degree video recording device and used it for this video. If you have an Android phone watch this video on that and see what happens as you move the phone around. If not then drag around the video to change your perspective (it might not work here, you might have to actually go to YouTube to see it.
Curriculum Tags: All https://www.youtube.com/watch?v=S3xOB-Bigc8

I don't miss a chance to say how good the activities that they are creating out of teacher.Desmos.com are and one of my faves is the Polygraph app. This one let's students play a "Guess Who" type game in pairs (each on their own device). They have their own premade ones (linear, quadratic and quadrilateral topics) but a new feature is that now you can create your own sets. As they say in their blog post: "Trust Teachers". That is, listen to what they are saying and asking for and we asked for customizable Polygraphs. So that is out now. Take a look. Thanks to @marybourassa for pointing to this one.
Curriculum Tags: All http://blog.desmos.com/post/122854798480/polygraph-custom-edition

Understanding data is so important now more than ever. We are generating more data now than we ever have. So the folks at the Five Thirty Eight blog have started a new podcast: What's the Point. On it they discuss the good, the bad and the ugly about "big data". So far they only have a few episodes but in them they talk about the importance of Data (Ep 0 - with Nate Silver), using data in science (Ep 2 - with Neil Degrass Tyson) and how New York City has used data to their advantage (Ep 3)
Curriculum Tags: Gr7, Gr8, MBF3C, MDM4U, MAP4C http://fivethirtyeight.com/datalab/introducing-fivethirtyeight-newest-podcast-whats-the-point/

And to finish of a "somewhat" balanced article on the benefits of discovery vs drill and kill. It seems this University of Winnipeg prof is always saying to drill them is the best. And it is funny that her headlines come from saying discovery is the problem for lower math scores but then quietly says that she has no proof of this. Some nice stuff from Dan Meyer and Cathy Bruce here on the discovery side as well.
Curriculum Tags: All https://ca.news.yahoo.com/old-school-math-teachers-debate-best-methods-scores-080010219.html

Another nice one for probability is this TED-Ed video on a simple probability game with dice. I love that the answer is counter intuitive. But this would be a good lesson when talking about fair games and depending on how you handle the math could be done in grades as low as seven and up to twelve. And don't forget that on the TED-Ed site there are follow up questions and teacher resources to go along with the video. Thanks to Mike Lieff for this one.
Curriculum Tags: Gr7, Gr8, MBF3C, MDM4U http://ed.ted.com/lessons/the-last-banana-a-thought-experiment-in-probability-leonardo-barichello

This is cool (and creepy). This abandoned Ferris Wheel just continues to spin on its own from the wind. You could easily model a nice trig functions problem off of it. Thanks to Xui Bai Li for this one
Curriculum Tags: MCR3U, MHF4U https://www.youtube.com/watch?v=n3Hj0Z23qys

If you are talking about surface area then this might be a neat little clip to show. The Mythbusters attacked the "It went over like a lead balloon" saying by making a balloon from lead and showing that it will float. Thanks to Jake Parlette for this one
Curriculum Tags: Gr7, MPM1D, MFM1P, MBF3C, https://www.youtube.com/watch?v=HZSkM-QEeUg