Finally. I've been saying this should be done for ages[1]
[1] Here's a 2010 blog post I made saying "do matlab in JS, make money". http://www.puremango.co.uk/2010/10/ten-ideas/
[1] Here's a 2010 blog post I made saying "do matlab in JS, make money". http://www.puremango.co.uk/2010/10/ten-ideas/
[1] http://wakari.io [2] http://github.com/ContinuumIO/bokeh
(just to be clear - I know mathics is a hosted solution, and uses Sage. I'm asking, does this meet your 'user friendly enough' criteria)
Beta testers wanted!