@mdehoon or @efiring can you take a look at this?

I don't have homebrew python installed; right now I have Anaconda on my path, and if I do
python simple_plot.py
I see the behaviour described by @sashkab , but if I do
python.app simple_plot.py
everything works normally. So, it would seem that @sashkab is invoking a non-Framework build. Googling, I see references to a --framework option to brew install python, but looking at the latest python.rb, I do not see that option. Does the brew install, like Anaconda, have both forms of executable, python and python.app?

@efiring --framework is default install method in brew. Please see python.rb#L76.
System python doesn't come with python.app and observes exactly same behavior as one I built with homebrew.

Can you try

import sys
print sys.executable
This may tell you if your Python is installed as a framework.

For example, with Anaconda:

efiring@manini2:~$ python
Python 2.7.6 |Anaconda 1.9.1 (x86_64)| (default, Jan 10 2014, 11:23:15) 
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> print sys.executable
/Users/efiring/anaconda/bin/python
>>> 
efiring@manini2:~$ python.app
Python 2.7.6 |Anaconda 1.9.1 (x86_64)| (default, Jan 10 2014, 11:23:15) 
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> print sys.executable
/Users/efiring/anaconda/python.app/Contents/MacOS/python
>>> 

@mdehoon Here it is.

~ $ python
Python 2.7.6 (default, Feb 21 2014, 21:09:35)
[GCC 4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.38)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.executable
'/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python'

@sashkab

System python doesn't come with python.app and observes exactly same behavior as one I built with homebrew.

You probably want to try system's pythonw interpreter for that.

I'm going to close this; the solution is to use pythonw if one has an installation (on OSX) that is not already making pythonw and python functionally identical. There is nothing we can do about it on the matplotlib side.