Okay, here's a little weird internet trend for you.  There is all of a sudden a proliferation of "Harlem Shake" videos.  Most follow a simple progression and use the same music.  Everything you need to know about this very weird phenomenon after the break.

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Okay, so there used to be a real dance called "the Harlem Shake".  Go ahead and put that aside for now, it has little to nothing to do with this current trend.  The current trend is a thirty second music bed.  It usually starts with one person in some kind of helmet of mask getting down.  No one else even seems to be paying attention as the masked man busts a groove. About :15 seconds in, everybody busts out in weird dances (and sometimes costumes).  Then, when you get to the :28-:29 second mark, everything kicks into slo-mo and you're done.

So, there's an internet phenomenon that exists no doubt because there is just a vacuum out there and something had to fill.  Resist the urge to do it, but no doubt somebody in your school, office or club will suggest you do a "Harlem Shake" video.