----------------------
Web As a Shell is a shell that that lives inside your browser to run API calls to different web services. It runs on WebSQL and many cool open source libraries. It was inspired by the try.mongodb.com.
GitHub: http://edisonw.github.com/Web-as-a-Shell
Disclaimer: This is one of those projects that you just use it for fun and not intended to have much practical usage.
-----------------------

Features:

User system: you can create and login as different users. After you login, everything saved as a user's preference will be encrypted by a encrypted key that is encrypted by your password. (similar to how SSL works) The password is only persisted in each session.
A modular drop in handler system: To make a new command, simply make it and drop it into the /js/handlers folder. Every time you call a command, it will be initialized and downloaded at that time. If you have updated the handler, you just have to call the reload command.
File system and built-in support for Dropbox (not done yet): Can authenticate with Dropbox with a api key/secret (that you can store encrypted in your user preference); list the files, and download or upload certain files. Files can be saved in base64 as user preferences and use to upload to other web services. *support for lstat etc in the future?
Twitter handler that posts and checks twits via web-shell's command line. (planned)
...only works in Chrome at the moment.