I was at a college football game years ago with some friends and we got into this fit of laughter when we started thinking about the fact that we stand and yell "wooohooo!!!" and "ALRIGHT!!" while we clap and smile when we're expressing ourselves (like at a football game.) We thought it was funny to analyze that behavior, like, why shouting and clapping as opposed to something else...but I ran across this today and it reminded me of that.
http://www.youtube.com/watch?v=O97_4xoYq8A