sudo pip install <stuff> with a restrictive umask set can cause this issue

gistfile1.txt

shredder ~ $ umask
0022
shredder ~ $ sudo pip install django # random package, for illustration purposes
Downloading/unpacking django
  Downloading Django-1.3.tar.gz (6.5Mb): 6.5Mb downloaded
  Running setup.py egg_info for package django
    
Installing collected packages: django
  Running setup.py install for django
    changing mode of build/scripts-2.7/django-admin.py from 644 to 755
    
    changing mode of /usr/bin/django-admin.py to 755
Successfully installed django
Cleaning up...
shredder ~ $ python2
Python 2.7.1 (r271:86832, Apr 15 2011, 12:09:10) 
[GCC 4.5.2 20110127 (prerelease)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import django
>>> dir(django)
['VERSION', '__builtins__', '__doc__', '__file__', '__name__', '__package__', '__path__', 'get_version']
>>> 
shredder ~ $ sudo pip uninstall django                                                                                        
Uninstalling Django:
  /usr/bin/django-admin.py
  /usr/lib/python2.7/site-packages/Django-1.3-py2.7.egg-info
  /usr/lib/python2.7/site-packages/django
Proceed (y/n)? y
  Successfully uninstalled Django

# Obviously, this worked fine.

shredder ~ $ umask 0027
shredder ~ $ sudo pip install django
Downloading/unpacking django
  Downloading Django-1.3.tar.gz (6.5Mb): 6.5Mb downloaded
  Running setup.py egg_info for package django
    
Installing collected packages: django
  Running setup.py install for django
    changing mode of build/scripts-2.7/django-admin.py from 640 to 755
    
    changing mode of /usr/bin/django-admin.py to 755
Successfully installed django
Cleaning up...
shredder ~ $ python2
Python 2.7.1 (r271:86832, Apr 15 2011, 12:09:10) 
[GCC 4.5.2 20110127 (prerelease)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import django
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named django
>>> 
shredder ~ $ ls -l /usr/lib/python2.7/site-packages/ | grep django
drwxr-x--- 17 root root   4096 May 25 19:40 django

# The django module is only readable by root the user and root the group; it is installed, but only root can actually use it!