.../projects/debian-addon/files/archive-key.asc | apt-key add -
Then update indexes with:
apt-get update
After that You can install any packages:
apt-get install <package-name>
Available ackages:
http://sourceforge.net/projects/updeb/
http://sourceforge.net/projects/install-debian/
http://sourceforge.net/projects/rpg/
http://sourceforge.net/projects/flashstreamer/
http://sourceforge.net/projects/process-progeny/