Even if you're not familiar with British comedians Morecombe & Wise you have to watch this, their best sketch. It's from the 1970's with Andre Previn where Eric Morecombe 'plays' Grieg's Piano Concerto. The timing is impeccable and my favourite lines are:

"In the second movement: not too heavy on the banjoes!"

and:

Andre Previn (or Andre Preview as they keep calling him): "You're playing all the wrong notes."      Eric Morecombe: "I'm playing all the right notes, but not necessarily in the right order!"

I remember seeing this as a kid watching with my grandmother. Her view on Mr Previn?

"He wasn't behind the door when noses were given out!"

On a personal note: we'd have been precariously related to Andre Previn at one point as distant cousin Mia Farrow was married to him!