Has anyone been to Redbull's Flugtag?

I want to go to Redbull's Flugtag in Chicago, but I have never been before. In the commerical it shows people sitting on bleachers. However, I dont know if the commerical was filmed in Chicago. At the Chicago Flugtag are there bleachers to sit on or should I bring my own lawn chair? Also, how early did you get there to get a good seat?