Rehab by Glee Cast is in Ab at 94 beats per minute and runs 5:38 across 124 bars. It uses 14 chords — Eb, Fm, Bbsus4, Bb, Ab7, Ab, G, Cm, 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? Rehab guitar melody tab.