This gif is just an approximation of the hysteria. I couldn't screen cap fast enough to do the whole thing
Link to the video and all the Chris Brown vids. (For some reason, MSNBC embed code doesn't work here)
Chris Brown singing "Run It" with David Gregory dancing at 3:08 and also near the end. Thanks to arealqt9 for finding this on youtube and sharing it with us.
The first time he danced on air, to Mary J. Blige