For me, having to go to a port-a-pottie at a show is the most dreadful part of the experience. Even more so than parking or paying $12 for a beer, it's the bathroom. Well this could be the answer to the dilemma of "can I get a clean john for a minute?!"
Numberphile got Dr. Ria Symonds and she did a breakdown of what to do in this situation, how your odds are going to be of scoring with the cleanest toilet possible and how to help yourself avoid the one stall that makes you wish you hadn't picked it.
And Numberphile gave us a choice in the video to watch the math in action, which is this video.
The numbers don't lie! Of course the best option is to train yourself to hold it and not go. That can get a bit tricky after a day of those $12 beers or whatever else you might have, so playing by the numbers is a good idea.