You complete me is pretty cool, it helps alot with my vim workflow, so I'll do a breif show of how to install it. Its really simple, and only installs for your user too, so you can use it on shared machines.

I will asssume Vundle is already installed. First add this in the vundle section of your .vimrc

Plugin 'ycm-core/YouCompleteMe'

Now launch vim and run

:PluginInstall

Go down to Youcompleteme and hit enter, and it'll take a second to install. If you get an error saying how the YCM server failed to start, you may need to compile YCM. Its not hard. Run this command

. ~/.vim/bundle/YouCompleteMe/install.py

You should see CMake go to work installing everything, and once it finishes you can use YCM! Hope this helped, that end issue of running that install.py tripped me up till I found it!