I borrowed the idea from Bob Lochel to have my Accelerated Algebra 2 students write a review of Desmos.com's online calculator. We only used it once in class so far, but the kids loved it. They wrote some great reviews. I cut and pasted some into a google doc found here.
If you haven't tried Desmos yet, what are you waiting for?
We were looking at all the graphs we are going to be working with this year and added sliders to see the transformations.