I took this video last night for you. It's only a minute or so, but multiply it times 12 hours, and you get some idea. If you could harness the energy of small boys, you could probably power cities...
https://www.flickr.com/photos/pyjammy/6325198085/in/photostream/
(and I wonder why their pajama pants all have holes in one knee?)
Re: ougrad...boys!