NodeBox (http://nodebox.net/) is an fun tool to experiment with 2D graphics. NodeBox version 1.0 only runs on Mac OS X, but a beta version of NodeBox V2 found on the NodeBox research Wiki ( http://research.nodebox.net/Home) runs on both Windows and Mac OS X (via Jython).
Before I knew NodeBox version 2 existed, I used Visual Studio 2005 to create a demo WinForms app that used GDI+ (System.Drawing) and IronPython. I plan on using this tool to play with some ideas on visualizing data.
A screenshot of NodeBox V1