I know that issues like this one are usually on the users(my) fault, but I think pip might be broken this time for real.

Every time I run pip install, a 404 error is raised:

(venv) /tmp wil
>>> pip install flask
Requirement already satisfied (use --upgrade to upgrade): flask in /home/wil/Programming/open/skinner/venv/lib/python3.5/site-packages/Flask-0.11_dev-py3.5.egg
Downloading/unpacking Werkzeug>=0.7 (from flask)
  HTTP error 404 while getting https://pypi.python.org/simple/packages/source/W/Werkzeug/Werkzeug-0.9.6.tar.gz#md5=f7afcadc03b0f2267bdc156c34586043 (from https://pypi.python.org/simple/werkzeug/)
Cleaning up...
Exception:
Traceback (most recent call last):
  File "/home/wil/Programming/open/skinner/venv/lib/python3.5/site-packages/pip/basecommand.py", line 122, in main
    status = self.run(options, args)
  File "/home/wil/Programming/open/skinner/venv/lib/python3.5/site-packages/pip/commands/install.py", line 278, in run
    requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle)
  File "/home/wil/Programming/open/skinner/venv/lib/python3.5/site-packages/pip/req.py", line 1197, in prepare_files
    do_download,
  File "/home/wil/Programming/open/skinner/venv/lib/python3.5/site-packages/pip/req.py", line 1375, in unpack_url
    self.session,
  File "/home/wil/Programming/open/skinner/venv/lib/python3.5/site-packages/pip/download.py", line 547, in unpack_http_url
    resp.raise_for_status()
  File "/home/wil/Programming/open/skinner/venv/lib/python3.5/site-packages/pip/_vendor/requests/models.py", line 795, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
pip._vendor.requests.exceptions.HTTPError: 404 Client Error: Not Found

/home/wil/Programming/open/skinner/venv/lib/python3.5/site-packages/pip/basecommand.py:158: ResourceWarning: unclosed <ssl.SSLSocket fd=4, family=AddressFamily.AF_INET, type=2049, proto=6, laddr=('10.0.0.6', 52061), raddr=('23.235.44.175', 443)>
  exit = UNKNOWN_ERROR
Storing debug log for failure in /home/wil/.pip/pip.log

With flask-sqlalchemy as a example.

Right: 

https://pypi.python.org/packages/source/F/Flask-SQLAlchemy/Flask-SQLAlchemy-2.0.tar.gz#md5=06ae73194cca73b72e178f870d1dac7c

PIP(wrong):

https://pypi.python.org/simple/packages/source/F/Flask-SQLAlchemy/Flask-SQLAlchemy-2.0.tar.gz/#md5=06ae73194cca73b72e178f870d1dac7c

Notice the simple added after to .org and the / added after .tar.gz