Just Someone I Used To Know by Jack Clement is in Bb at 110 beats per minute and runs 2:07 across 52 bars. It uses 5 chords — Bb, C, F, C7, F7. 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? Just Someone I Used To Know guitar melody tab.