Apparently some students in Finland made up a religion as a joke, it didn't get "Official" status since you would need set amount of registered believers to do that but they did find use for it. One of the students was told to remove his hat while indoors so they simply wrote a letter to the headmaster saying that their religion demands that everyone of them must wear a hat at all times. Apparently the headmaster either took this seriously, or felt that arguing with them would be more trouble than it is worth and they were allowed to wear hats indoors.