As a percussion student at the Guildhall School of Music and Drama in London in the early 80s, I took part in a college production of Bernstein's 'Mass'. A wonderful mix of rock, jazz, big band, strings and percussion, and of course acting and singing.
The piece was performed in our stripped out theatre, 'in the round' around a street crossroads set which quartered both the musicians and the audience seating. In one corner was the string section, in another the wind and brass, in another the rock band and timps and perc had a whole section (and needed it). The action was played out on the narrow strips of roadway separating these sections. Imagine a cross shaped fashion catwalk with musicans as guests and you'll get the picture.
The West Side Story feel ran throughout the piece.
Bernstein showed up unexpectedly during reheasal and conducted a session. The difference in the approach and resulting performances of all concerned was stunning. The public performances were great, but none of them got near the electricity generated with the composer on the rostrum.
I once heard a critic suggest that Bernstein was the only conductor one could identify unseen. I would have to agree.