I have been working with the Callysto project, which involves fostering computational thinking and data science within the regular curriculum for grades 5 to 12. One of the services provided by Callysto is the Callysto Hub, a free online environment hosting an open-source instance of Jupyter Hub that allows you to run, edit, and create Jupyter notebooks such as these.
While some commercial platforms have good sharing options, there isn't currently a great open-source solution for sharing Jupyter notebooks with collaborators and students. I can show you my current workflow, though, for creating, editing, and sharing Jupyter notebooks.
There are two programs I have installed on the computer in front of me Visual Studio Code for running and editing Jupyter notebooks on this computer and GitHub Desktop for synchronizing with GitHub.
We'll start with GitHub, this is the site used by many software developers to share and collaborate. You'll need to create a free account.
Next we'll use the GitHub Desktop application. Download, install, and run it, then log in with the GitHub account you just created. Now when you visit a GitHub repository, such as Callysto Curriculum Notebooks, you can click the green Code button near the top right of the page and then Open with GitHub Desktop. It should pop you back into the GitHub Desktop program, and you can click the Clone button to download the code from that repository.
To set up Visual Studio Code, download and install it. You'll also need to download and install Python, the VS Code Python Extension, and the VS Code Jupyter extension. You should then be able to open, run, and edit Juypter notebooks, as well as create new ones.
If you encounter errors running notebooks, you likely need to install some Python libraries with commands like !pip install pandas , post in the comments (or reach out on Twitter) for help with that if you need.
At this point you're basically set up, but it gets a little more complicated if you want to share notebooks you create. You'll want to create a new GitHub repository, add your notebook file to that repository folder on your computer, and use GitHub Desktop to commit and push it to GitHub.
Once the notebook file is on GitHub, you can either have your students or colleagues go through this setup process to download your new repository, or you can send them a Callysto nbgitpuller link.
Hopefully that's not too complicated, but feel free to reach out if you have questions or would like help with this.
(Updated for 2022)