Some professional actors could read any page in any phone book. With their skills of pronunciation, intonation and selective silence, that passage of words could sound like the most titilating, most outrageously incindiary phrase ever uttered in history!
Ah...I know exactly what you are talking about there-I have seen that exercise, and I cannot remember who did it.
It might have been John Cleese doing that, taking some banal piece of text or an ad out of a newspaper, and while reading it, doing exactly as you described, raising and lowering his voice, putting accents in all the right (wrong) places, but...what really made it was his facial expressions as he did so! The eyebrows and all...