We've got a present for all of our paying customers -- if you celebrate Christmas, you can call it a Christmas present, and if you don't you can just call it a present :-)
IPython notebooks are now available on all paid accounts on PythonAnywhere. Give them a go! You can start a new one, or run one that you've saved or uploaded, from the "Files" tab. It's a new feature, so we're particularly keen on hearing any feedback you'd like to send us.
If you're not a paying customer yet, you don't need to feel left out -- we'll be supporting them (perhaps with a couple of limitations) on free accounts in the New Year.
Happy holidays to everyone, and we look forward to seeing you in the New Year.