Counting the human voice as an instrument:

1)Pat Boone's cover of 'Ain't that A Shame' really IS a shame, and

2)I once was trapped in a car on a Michigan-to-Maine road trip with a big-time Carpenters fan (he'd never let on before!)--did you know that they did a cover of 'Dead Man's Curve?' 52-part harmony; precise, clipped vocals, and all...it was enough to MAKE you want to drive off a cliff...