To install the latest release using command-line, just use the instructions below:
First, edit the /etc/apt/sources.list file and enter your user password:
sudo nano /etc/apt/sources.list
Add the following two lines (the second one is not necessary, unless you want the sources to be available too):
deb http://ppa.launchpad.net/openoffice-pkgs/ppa/ubuntu jaunty main
deb-src http://ppa.launchpad.net/openoffice-pkgs/ppa/ubuntu jaunty main
Add the trusted key for these repositories:
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 247D1CFF
Update the packages lists:
sudo apt-get update
You can eventually remove your existing OpenOffice installation by using the following two commands:
sudo apt-get remove --purge openoffice.org
sudo apt-get autoremove --purge
This will also remove system-wide configuration files.
Now, install OpenOffice.org 3.1.1:
sudo apt-get install openoffice.org
This should be all. You can run it by pressing Alt+F2 and typing openoffice in the run box.