We recently added something cool to PythonAnywhere, our Python online IDE and web hosting environment -- if you're writing a tutorial, or anything else where you'd find a Python console useful in a web page, you can use one of ours! Check it out:
What's particularly cool about these consoles (apart from the fact that they advertise the world's best Python IDE-in-a-browser) is that they keep the session data on a per-client basis -- so, if you put one on multiple pages of your tutorial, the user's previous state is kept as they navigate from page to page! The downside (or is it an upside?) is that this state is also kept from site to site, so if they go from your page to someone else's, they'll have the state they had when they were trying out yours.
Bug or feature? Let me know what you think in the comments...