weirdest/craziest "house rule" you have seen?

A new player recently came to my LGS after moving to the area. After sitting down at our table, he asked if there were any "house rules". I asked him what he meant, and he explained his old LGS had a short ban list of cards people couldn't play at their commander nights(mostly mass land destruction he said). But also, there was a standing rule that you couldn't counter someone's commander the first time they cast it in a game.

This made me curious since I've never played at a shop with any rules/restrictions like this. So what're some weird or crazy "house rules" you've seen?