In the 50s, things were different. As long as you kept your nose clean, you could get away with a lot. Even if you're flying the Dash 80 prototype to which Boeing's whole livelihood rests. How does Tex Johnston sell the 707 to potential customers? "The Gold Cup Roll".

Cool. I always wanted to do a barrel roll in my C-130, but never had the balls to do it (or the right crew who would keep their trap shut).
I was just reading about that guy, pretty ballsy but pulled it off
In reply to johndej:
As he states, done correctly its a constant 1G maneuver, the plane never knows its upside down.
Here's a better quality video.
https://www.youtube.com/watch?v=AaA7kPfC5Hk
Its claimed that last words to the test pilot before the maiden flight of the 777 was "No rolls!"
this "recommended" video from that page got my attention:
http://www.youtube.com/watch?v=ar-poc38C84
C-130? I got your C-130s right here. Hercules & The Four Horsemen