They constantly sell the obvious stuff… you know like t-shirts, food, and beverages.

Then they sell some other kinda obvious stuff… like display advertisements (usually people that want main stream press like Pepsi and Verizon) and booth rentals (people selling cool t-shirts or Best Buy).

The newest thing I saw them selling was movie trailers.  During the intermission they were displaying the “Devil” movie trailer.

Then the smartest thing they do is promote their other concerts.  On the back side of the concert schedule it is filled with their next concert.  On the way out they hand us 3-4 other concerts to look out for.

Concert venues know that the people most likely to go to your next concert are the people that are currently at the concert.