Graphical front end for installing local Debian packages. DebInstaller is a graphical frontend that allows easy installation of downloaded Debian packages. Far to often are people (read: newbies) confused when they can't get *insert favorite package manager* to install the .deb's they've just downloaded.
With DebInstaller installation is simply a double click away. No fancy features, just a small dialog that ask for root password and if you really want to install.
Since DebInstaller is still under heavy development, you might be interseted in the alternative program gdeb.