Here's what the free burger insanity at 500 Degrees looked like around 11:30 a.m. yesterday - this is at the corner of 15th and Sansom Streets. According to intrepid tipster and burger enthusiast Russakoff Rules, the line snaked all the way down 15th Street toward Walnut. All told, over 600 burgers were served throughout the day. Did anyone sample the wares? Let us know in the comments.