As we've seen time and time again, when you get people together for a gig, random things will happen.
It could be something as simple as cheering on a car-park announcer, serenading female police officers or, in this case, rowing imaginary boats in the middle of a moshpit at Download Festival during someone's set. The video shows a couple of people on the ground rowing, and before long, nearly half the crowd is at it.
As you do. Take a look.