Build and host a processing.js app in your browser with AppJet
processing.appjet.net
processing.appjet.net
This is in the spirit of Processing, which itself is all about by-passing unneeded complexity to make cool stuff.
Even (or especially?) for hackers, it's fun to have an environment to play around in without a lot of set-up. Granted, a lot of existing in-browser IDEs don't live up to their potential, but AppJet has a chance to be different in this regard.
As easy-to-use libraries and frameworks like Processing and AppJet catch on, I think they will be of use to a lot of people who don't already have a shell window open to a web server somewhere.
My brilliance is blinding.