For those of you teaching function transformations in Algebra 2 (or even Algebra 1?), check out this slick Desmos resource called Des-man that they put together recently with Dan Meyer and Christopher Danielson. I know a number of teachers at my school who have done something similar to this over the years, even with the Desmos.com graphing calculator. What's slick about this is that it provides a nice short demo for kids to see how to constrain the domain and range, and it allows you as a teacher to set up a "class" and see all students projects in real time. Very cool!
Another Desmos-made activity I found this summer is an activity called "Penny Circle" that uses best fit sliders to find a function that optimizes number of pennies fitting into a circle of given radius. It works out to be quadratic, I believe. Again, a very slick and kid friendly/intuitive activity. I'm going to do this with students in my quadratics chapter this year.
I'm VERY impressed with what's coming from Desmos these days. Free online graphing calculator (that's superior to TI-84s, IMHO) aside, they are really delving into quality technology based instructional activities that are way better than listening to some guy drone on in a grainy video lecture full of mistakes. And they are doing it without financial support from the likes of Bill Gates and Bank of America (I'll let you read between the lines there).