Ubuntu 14.04's Python 3.4 installation has a problem with ensurepip module, as described in this bug. So if you follow the steps mentioned in the official documentation, you would see an error message like this

➜  Python  python3 -m venv py3.4venv
Error: Command '['/home/thefourtheye//py34venv/bin/python3', '-Im', 'ensurepip', '--upgrade', '--default-pip']' returned non-zero exit status 1

To resolve this problem, first install the venv, without pip, like this

python3 -m venv py3.4venv --without-pip

And then if you install pip, like this, it will still fail

(py3.4venv) ➜  py3.4venv  python -m ensurepip --upgrade
/home/thefourtheye/Python/py3.4venv/bin/python: No module named ensurepip
(py3.4venv) ➜  py3.4venv  python
Python 3.4.0 (default, Apr 11 2014, 13:05:11)
[GCC 4.8.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
...

So, you need to install, pip separately, like mentioned in the pip's official documentation. So, the actual list of steps go like this

➜  Python  python3 -m venv py3.4venv --without-pip 
➜  Python  cd py3.4venv 
➜  py3.4venv  source bin/activate
(py3.4venv) ➜  py3.4venv  wget https://bootstrap.pypa.io/get-pip.py
--2014-12-30 14:35:34--  https://bootstrap.pypa.io/get-pip.py
Resolving bootstrap.pypa.io (bootstrap.pypa.io)... 103.245.222.175
Connecting to bootstrap.pypa.io (bootstrap.pypa.io)|103.245.222.175|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1581355 (1.5M) [text/x-python]
Saving to: ‘get-pip.py’

100%[=====================================================================================================================>] 15,81,355    129KB/s   in 8.9s   

2014-12-30 14:35:43 (173 KB/s) - ‘get-pip.py’ saved [1581355/1581355]

(py3.4venv) ➜  py3.4venv  python get-pip.py 
Collecting pip
  Downloading pip-6.0.3-py2.py3-none-any.whl (1.3MB)
    100% |################################| 1.3MB 139kB/s 
Collecting setuptools
  Downloading setuptools-9.1-py2.py3-none-any.whl (552kB)
    100% |################################| 552kB 180kB/s 
Installing collected packages: setuptools, pip


Successfully installed pip-6.0.3 setuptools-9.1
(py3.4venv) ➜  py3.4venv  deactivate 
➜  py3.4venv  source bin/activate                      
(py3.4venv) ➜  py3.4venv  pip install django
Collecting django
  Using cached Django-1.7.1-py2.py3-none-any.whl
Installing collected packages: django

Successfully installed django-1.7.1
(py3.4venv) ➜  py3.4venv  which pip
/home/thefourtheye/Python/py3.4venv/bin/pip
(py3.4venv) ➜  py3.4venv