There are all sorts of horrendous medieval or high-tech punishments you can mete out on characters in a game. But sometimes the best ones are the simplest, those that strike a chord with the players. Having a character drawn and quartered is kind of abstract, but having one be made to sit in the naughty chair with their nose to the wall is profoundly embarrassing and visceral. Especially if you do it to a noble in the King's court.