Google Chart API
The Google Chart API is an extremely simple tool that lets you easily create a chart from some data and embed it in a webpage. You embed the data and formatting parameters in an HTTP request, and Google returns a PNG image of the chart. Many types of charts are supported, and by making the request into an image tag you can simply include the chart in a webpage.
Originally it was an internal tool to support rapid embedding of charts within Google's own applications (like Google Finance for example). Google figured it would be a useful tool to open up to web developers. It officially launched on December 6, 2007.[1]
Currently, line, bar, pie, and radar charts, as well as venn diagrams, scatter plots, sparklines, maps, google-o-meters, and QR codes are supported.
Example Chart
The following URL creates the pie chart below.
http://chart.apis.google.com/chart?chs=200x200&chdlp=b&chtt=Uberman&chdl=Asleep%7CAwake&chd=t:1,11,1,11,1,11,1,11,1,11,1,11&cht=p&chco=586F8E,7D858F,586F8E,7D858F,586F8E,7D858F,586F8E,7D858F,586F8E,7D858F,586F8E,7D858F