Proposed by Alexander Bautz, a client side charting solution for SharePoint that relies on the Google Visualization API.

To understand the difference between the Google Chart API and the Google Visualization API, check out this page:
http://code.google.com/apis/charttools/docs/choosing.html

This is a solution for creating charts directly from SharePoint lists using Google Visualization API. The solution is a CEWP-solution and requiring no other than a few script references. All code and data are processed and rendered in the browser. No data is sent to any server.[…] You can pull data from any existing list view (even from personal views – for personal use), or using a custom CAML-query … Read More

via SharePoint JavaScripts