Here's the idea: A man is going to be attached to a rope dangling from a pole and then fall. The rope is totally loose and not attached to anything but there will be a weight rigged to the opposite end of the rope that holds the man. What happens? Does the man fall straight down? Nope! The rope swings around and tightens itself around the pole saving the man from plummeting to the ground. Duh. There are too many sharp cuts and slick editing in this video from NRK Viten (not to mention the life in danger thing) for me to believe that there wasn't any movie magic sprinkles on it but it's still pretty cool to see physics in application.
And here's how it works on a smaller, realer scale: