Craig Layne

1. Open terminal.
2. Add the repo:

sudo apt-add-repository 'deb http://archive.getdeb.net/ubuntu oneiric-getdeb games'
wget -q -O- http://archive.getdeb.net/getdeb-archive.key | sudo apt-key add -
sudo apt-get update

3. Install Games:

This will install them all:

sudo apt-get install marathon*

Or individually:

sudo apt-get install marathon
sudo apt-get install marathon2
sudo apt-get install marathon infinity

Congratulations, you have now installed the Aleph One engine, and the Marathon Trilogy. Enjoy some old school gaming.