The Rains Of Castamere by Sigur Ros is in Bbm at 80 beats per minute and runs 2:12 across 36 bars. It uses 11 chords — Fm, Ab, Bbm, C5, Csus, Db, Fsus2, Dbmaj7, and a few more. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? The Rains Of Castamere guitar melody tab.