Launchpad Entry: https://blueprints.launchpad.net/ubuntu/+spec/frets-on-fire
Package homepage: http://fretsonfire.sourceforge.net/
Frets on fire is a game similar to Guitar Hero but you play it with the keyboard (or the usb controller from Xbox 360). This game would make a nice addition to the list of games shipped with ubuntu.
There are licence issues with the music content of the game which need to be considered.