Really Cloudy is a library that lets you pass processing work to your website visitors. Rather than paying to have your data crunched by Amazon you can distribute the load for free.
Your users don't have to install anything to join the processing cloud - it's all done automatically with JavaScript in the background using the new Web Workers API.

Code: Really Cloudy is an open source proof of concept. You can get the code from GitHub.
Ethics: At The Plan Is we don't use Really Cloudy without an explicit opt in by the user. By design the web workers API allows you to run background tasks without telling the user but that shouldn't be abused.