The Google Chart API lets you dynamically generate charts as PNG-format images.
To see the Chart API in action, open up a browser window and copy the following URL into it:
Several types of image can be generated: line, bar, and pie charts for example. For each image type you can specify attributes such as size, colors, and labels.
Pretty cool stuff. I fiddled around with this a bit and came up with this:
It’s the 2007 pageviews for this site. (Yes, I know I’m a month early!). A bit of a drop around the summer, but nonetheless the pageviews more than tripled over the year.
Anyway, check the Google Chart API page for more information and go create your own charts.