The popular fansite Henry Cavill News found their way into the stadium where the Gotham City/Metropolis football game was taking place for Batman vs. Superman at East Los Angeles College today, and brought some photo, video and details about the shoot.
First and probably most significantly, they related that when they sat fans down to explain what was going on, they referred to the film as Batman vs. Superman, seemingly reinforcing the theory ComicBook.com posited shortly after San Diego Comic Con International that Batman vs. Superman would be the film's name, or at least its working title, based on website and trademark registrations.
Whereas The Dark Knight Rises featured what seemed to be a professional football game being played at an NFL stadium, this film will apparently be operating at the college level; sweatshirts handed out to extras bore the names of Metropolis State and Gotham City University.
The site also took a few brief pieces of video that you can find at their Instagram page, including some shots of the film's director, Zack Snyder. One of them includes a look at the line, which HCN estimated to be around 200 people waiting to participate in the shoot, which took place on the day of an actual college game between Victor Valley College and East Los Angeles College; in many of the shots, you can see the ELAC Huskies logo (we assume those shots will be digitally altered, or those angles avoided altogether, by the actual film crew).
Taking cues from Smallville, it appears as though Metropolis wears red and gold (while, as ever, black and gold are Gotham's colors).