The Olympics have always done a great job at gathering the best athletes around the world to compete for gold. It's easy to not fully grasp just how great these athletes are which is why I'd love to see them throw in the average person into every competition (with the exception to those that can get people seriously hurt) and have those people compete with the worlds best.
This person would need to accept beforehand that there would be no chance for them but instead help showcase the difference. Hell, they could even be given participation medals.