Is there an online multiuser environment for coding/interacting with widgets?

People log in (to a web page), everyone sees these persistent composable widgets running javascript code, anyone can click on a widget and edit the code (if they have rights to that object).

Everyone viewing a room sees any movement or interaction that other people do on one of the widgets. Also, it would be nice if the widgets could generate other widgets (with code) so people could do dataflow programming and other interesting things just by composing and configuring widgets.

It would also be nice if you could export a set of widgets for inclusion in web pages. Since I'm mentioning things that would be nice, it would be nice if there was a convenient contextual socially intelligent autocomplete system for inserting the highest ranking (most insertions) widget matching your context (type of widget you are in?) and whatever you have entered so far.

I know if anyone responds to this they will probably just be explaining why they think its stupid, but I just wanted to check because I think about having this sort of thing all the time.