Frets on Fire

Frets on Fire is a freeware game of musical skill and fast fingers. The aim of the game is to play guitar with the keyboard as accurately as possible. Frets on Fire features unique inverted keyboard gameplay style, support for guitar controllers and generic joysticks, hundreds of songs composed by the community, and more.

Features
Unique inverted keyboard gameplay style
Support for guitar controllers and generic joysticks
Includes a song editor for making your own tunes
Compete with others on the World Charts
Hundreds of songs composed by the community
Supports importing Guitar Hero I and Guitar Hero II songs
Multiplatform; runs on Windows, Linux, Mac OS X and FreeBSD Open source, full Python source code available

Developer: Unreal Voodoo
Released: 2006
Official Website

Free Full Game Download:
GamersHell (v1.2.512 Windows - 32 MB)
GamersHell (v1.2.451 Mac - 38 MB)
GamersHell (v1.2.512 Linux - 36 MB)
Official link