If you want it to be a more social experience, pack along a parking lot game or two. Washers or Hillbilly Golf and bring a football. If you really want to get crazy bring a beer bong or something festive that makes your tailgate unique and draws people to it. It really is a big party though, especially in the reserved lots with the party busses. You can spend the whole afternoon jumping around b/cuz the parking lot is ridiculous. I've been a lot of NFL games and no tailgaters out tailgate the Chiefs, however, I am biased.