Its grown men playing with cardboard boxes that make a little flag do a little dance. Those grown men happen to be monks. And its so beautiful.
Making a little machine, also known as a toy, is such a basic human instinct. That's why kids dig 'em. And when are we a better version of ourselves than when we can think with an open heart, like a kid.
And yes, it did remind me of Rolf.
Here's a link to the exploratorium blog where the video lives.
And here's a link to more Cardboard Automata.
And here's a link to a modern master of the form, Arthur Ganson.