fyi there karaoke songs, essentially the mp3 is the sound track (with or with out words, what ever it i, it is) and the .cdg file is i beleive an uncompressed data stream of the graphic data for the song. I beleive they encode the grahic data into spare subchannel bits in an audo cd making it a cd-g, they still play like audio on a audio player, but have graphics if played in a cdg player, quite a clever trick, stinky 320x200 16 color screen i beleive, and takes like 25 seconds of song to fully display a 320x200x16 color image, so its not like there overly great graphics! (i think i began rambling didnt i)