From the liveleak site:
This is unreal. You're seeing about 2-3000 kids under 10 in the front doing intensely choreographed gymnastics moves, and look in the background. That's not a giant screen, that's thousands and thousands of children holding up sets of cue cards for the routine. I don't know what it is, but there's something frightening about this. | Children's section of 'Mass Games' or otherwise known as the 'Arirang' performance in Pyongyang city, North Korea in 2005. Watch the giant human mosaic in the background, composed of 15,000 or more individuals each holding a colored placard. The mosaic changes with the music.
This is just... freaky. And amazing.
ADDENDUM: Weird-- it's not embedding correctly for some reason. Go to the link-- it's a worthwhile click :)