Reductio ad Hitlerum

Not only does this Wikipedia article exist, it is going on 5 years old and has been edited over 600 times. I find this fantastic.

Grampa: "I can finally win a gold medal. I came close at the 1936 Olympics. I threw a javelin that barely missed Hitler. But I did hit an assassin who was trying to kill Hitler." Hitler (in 1936): "What is this, Kill Hitler Day?" Grampa: "The next time I saw Hitler, we had dinner and laughed about it."