What are ways to install/uninstall programs in Ubuntu. I will mention only .deb since it is the official package format and for example installing a .sh or .run program can typically be as simple as (In latest Ubuntu)
Also note that am talking about HOW to install packages IN Ubuntu, not talking about downloading a new installer (Like some Super Cow Software Center Duke Nukem version from sourceforge or something). Only tools that already come in the repositories (In any of the 4 standard ones, main, universe, restricted or multiverse).
Take into consideration all GUI and terminal ways of doing it, with basic format of doing the installation. With this in mind I am talking for example about Software Center, synaptic, apt-get, aptitude, dpkg, etc... a way to show all tools that are available in Ubuntu to install deb packages.
NOTE - Forgot, this should be Community Wiki since it will have all ways a user can install/uninstall something. Like a friendly guide on doing that.
UPDATED question to remove the confusion some are having about sh/run files.