1. Go to System-Administration-Software Sources, Third-Party Software tab, Add:
deb http://archive.getdeb.net/ubuntu karmic-getdeb games
2. Add the repository GPG key, open a terminal window and type:
wget -q -O- http://archive.getdeb.net/getdeb-archive.key | sudo apt-key add -
3.
sudo aptitude update && sudo aptitude safe-upgrade