The Akihabara you can download here is my personal dream too. It is a set of libraries, tools and presets to create pixelated indie-style 8/16-bit era games in Javascript that runs in your browser without any Flash plugin, making use of a small small small subset of the HTML5 features, that are actually available on many modern browsers.
I wrote this for fast game developing/prototyping, since Javascript is not only a funny scripting language but is also available quite anytime during the day, for some coding-on-lunch-break (my unique spare time).