A few years ago, I went to a camp by my school at a place not very far away. There was an activity that you stand for 8 minutes with your hands straight, holding a paper in front of your eyes and remain in a straight pose.
It was really hard. The teacher said we could sit down if we wanted to, and I could see people sitting down one by one. But many people stayed in there position, focusing on the paper only. My arms eventually screamed for rest. I was really weak then.
There was a lot of people standing until the end, but there was a lot of people who sat down also. The teacher that started this said it was going to be 5 minutes, but he only stopped us at 8 minutes. There was no prize for the winners, but I think I got the confidence to do everything from that activity.