Software installers

The GNOME software center doesn't allow you to install all available programs.

Install Synaptic to manage all installable programs and gdebi to install tird party .deb instalation files.

sudo apt-get install synaptic gdebi

managing ppa's using Y-ppa manager

sudo add-apt-repository ppa:webupd8team/y-ppa-manager

sudo apt-get update

sudo apt-get install y-ppa-manager