What I did to get Python 3.4.2 on Ubuntu 14.04. The stock version of Python 3 on Ubuntu is 3.4.0. Which is missing some of the best parts! (asyncio, etc). Luckily I discovered pyenv which solved my problem.
Pyenv (not to be confused with pyvenv) is the Python equivelant of rbenv. It lets you configure which Python environment/version is available per directory, user, or other session variables.
I followed the instructions here to install pyenv in my home directory. Verbatem, those instructions are:
sudo apt-get install git python-pip make build-essential libssl-dev zlib1g-dev libbz2-dev libreadline-dev libsqlite3-dev