Desmos makes graphing understandable!
Desmos can be used for so many things involving graphing. It keeps getting better.
I like the "Daily Desmos" website for inspiration.
How I Use It
I use Desmos for projects. I ask kids to get creative and create drawings using algebraic equations (lines, parabolas, etc). The kiods love it because they get to be creative and the interface is responsive.
The instructions and examples are clear.
Take a look at their gallery of drawings.