For some time I used PyChart, but due it's complexity and really odd api, I dumped it and get back to OpenOffice. Yes, I went back to stone age, from nice comfort of favorite editor to clicking on eat-all-available-memory OpenOffice.
From time to time, I stumble upon some library, but nothing I would be satisfied with. Until I found guile-charting.
Honestly, Guile is not my favorite package and I install it mostly to play with differences on Scheme implementations, but from no on, guile-charting will be probably the main reason why I will keep Guile package installed.
Here is the sample code (also on pastebin):
(use-modules (charting))and will produce this:
(make-bar-chart "Monthly status for Foo project"
You will also need guile-cairo for guile-charting.