Adobe AIR is a runtime environment that allows developers to create platform independent desktop applications based on existing web application technologies. Basically, it allows programs that would normally run inside a web browser to be run as desktop applications.
One very nice thing that the Adobe people did was to make their installer create a .deb or .rpm package if you're on a Debian based or RPM based Linux distribution. Because of that, these instructions should work on all Debian or Ubuntu based distributions as well as redhat/Fedora and SUSE based distros. Read more