NetworkX – “complex networks”, ie graphs, in Python.

NetworkX — graph creation, manipulation, rendering, and other funky stuff in Python. Looks like a nice toolkit for working with graphs, basically. Check the screenshots for “mmmm” and tutorial for “ooooh”.

(By the way, this is graphs in the “nodes and edges” sense, not the “plot y vs x” sense, for which, see gnuplot/ or (looks much better!) the pure python and very funkilicious matplotlib.)