The opening ceremony / entryway. 

GenCon *needs* to do something about that.  I didn't go in for about 5-10 minutes, and it was literally shoulder to shoulder immoveable mass of bodies.  This is 100% due to the location of FFG's booth, and it's proximity to the door.  That crowd, on that day, was the only time in my 17 years where I have actually been concerned for my safety, as it could very easily have turned ugly.