I know what you're thinking. Ok, I really don't.
But this is kind of old, but I found it while looking for something else. It's Murray Crewe, bass trombonist of my beloved Pittsburgh Symphony, talking through the history of his Conn contrabass trombone. The first amusing thing to notice is that they go hunting for him in the bar across the street. The second amusing thing is the sheer size of the instrument.
He's using it to play the famous impossible gliss in the Bartok concerto for orchestra- the gliss goes from B natural to F, an octave below the second partial on your average Bb tenor trombone, which doesn't quite hit any of the partials for a regular bass trombone, but hits the second partial on a contra. There's a brief discussion of the gliss here.