Frets on Fire according to the game 's developers "is a game of musical skill and fast fingers. The aim of the game is to play guitar with the keyboard as accurately as possible." It's basically a freeware version of Guitar Hero where your computer keyboard acts as the "guitar" controller. Check out the short video of my son giving it a test run on his Vista computer. Notice how he is holding his keyboard like a guitar- right hand pressing the enter key in time with his fingers on the left hand pressing the function keys
(I tried downloading the MacOSX version, but it caused my intel based iMac to crash...) UPDATE: Check out my post on how we got the game to work on my iMac.
In addition to the pre-loaded songs, you can also "compose" new songs with the game's built in song editor and Ogg Vorbis files. I had a blast trying to play Nirvana's "Smells Like Teen Spirit". It's surprisingly well done for a freeware program.