NodeBox is an open-source, node-based software written in Python. The beta release of version 2.0 is available at http://beta.nodebox.net/ which seems to put more focus on generative art:
“NodeBox is a Mac OS X application that lets you create 2D visuals (static, animated or interactive) using Python programming code and export them as a PDF or a QuickTime movie. NodeBox is free and well-documented. […] The NodeBox Graph library includes algorithms from NetworkX for betweenness centrality and eigenvector centrality, Connelly Barnes’ implementation of Dijksta shortest paths (here) and the spring layout for JavaScript by Aslak Hellesoy and Dave Hoover (here). The goal of this library is visualization of small graphs (<200 elements), if you need something more robust we recommend using NetworkX.”
Note to myself: upgrade my Python&skills (3.0), then check it out in-depth!