Building charts on control pages

Didn't see a thread on this anywhere. I'd like to know what everyone is using for drawing charts on control pages.

I use JpGraph (http://www.aditus.nu/jpgraph/) not in conjunction with control pages but it can save images, for example to the IndigoWebServer/images directory. It's free, php based (CLI compatible). You'd need to refresh the saved image periodically. It's fast, much faster than another php based solution that I forget the name of.