I don't know for sure if this is matplotlib's fault. ipython's fault or Mac OS X, but I ever since I upgraded to matplotlib 1.0.1 I have this problem that ipython will exit with segfault after I close a figure.
I have not found what exactly causes the crash, but it can happen with the simplest of figures.
This is one of those annoying intermittent problems: I can't replicate it with a sequence of steps.
I can often run days with the same ipython shell, generating many many figures without problems, and sometimes everytime I plot a figure, ipython segfaults out after the figure is closed.
The Mac OS X stack trace is attacked to the tracker ticket I opened