In an effort to make it easier to install the latest proprietary graphics drivers in Ubuntu, a new official PPA was released today.
Currently, the PPA ships Nvidia drivers only (and it's not clear if it will include other packages like AMD drivers, etc.) and is in testing. According to the PPA description, you should wait a few days before using this PPA.
In a message posted on the Ubuntu Desktop mailing list, Jorge O. Castro notes that currently there's no difference between this and the xorg-edgers PPA and that "the real fun begins when new drivers are released".
At the time I'm writing this article, the PPA provides the latest stable Nvidia driver (352.30) as well as the latest beta (355.06), along with libvdpau 1.1 and vdpauinfo 1.0, for Ubuntu 14.04, 15.04 and 15.10, with some older packages (Nvidia 346.87) for Ubuntu 12.04.
To add the PPA (but again, you shouldn't be using it until the PPA description says it's safe to do so), use the following commands:
sudo add-apt-repository ppa:graphics-drivers/ppa sudo apt-get update
and then use Synaptic / Ubuntu Software Center to install the Nvidia driver version you want to use.