The best surprises almost always come at singarounds/song sessions: the wall of harmonies when "Byker Hill" goes just right, the frisson when a guitarist puts an unexpected blues-like riff behind "Haul Away for Rosie", the eye-closing tension when a plainly nervous singer conveys the sheer murder of the industrial revolution, simply the best version of "Blue Tattoo" I've ever heard with two killer guitarists running the riffs round each other and a viper of a mandolin line nagging away to it, the cultural shock when our very own Wild Rover first put "The Wild Rover" to the tune of "Stairway to Heaven", the wash of emotion when Show of Hands' "Roots" rings off in harmony with an almost nightclub boogie from a chunk of bodhrans, the thrill as a whole pub goes into an awed hush for an (unnamed for this purpose) female singer as she hits every note of a traditional song like a big bell.