The CodeHS Sandbox is a place where you can write programs outside of the bounds of an exercise. In the Sandbox, you can start a program starting from scratch in any of our programming languages and create anything that you can imagine.
To access the Sandbox click on the "Sandbox" link in the top left corner of any page.
The Sandbox is also a great place to send students to work on their own free-form projects, once they've covered some of the basic curriculum through CodeHS. Teachers have also had their classes take on midterm or end of year projects through the Sandbox.