I've never really considered writing a blog post about Desmos.com because I figured people would just go to their site to learn. But it might be beneficial to see how other teachers are using it.
Yesterday I gave my Algebra 1 students a test on graphing with slope-intercept. The averages of the classes were 75% for the one class and 65% for the other class. Clearly, they weren't ready for the test. I decided that this topic is too important to ignore so we are re-learning and re-assessing on the topic.
This is a link to the desmos activity.
**Note** Be prepared for inappropriate drawings on the activity. Period 3 thought it would be funny to draw a penis for all to see. ((sigh))