Board games are a great way to learn some valuable life lessons, like losing with good grace. This doesn't come easily to most people, so plenty of practice is needed! In order to make sure that we have fun, we have a few family rules which help to encourage us all to treat each other well.
1) Mummy usually wins. It is best if you accept this before you start, especially if the game is Settlers of Catan.
2) We won't let you win. The children get to learn how to lose graciously the hard way (SLOWLY learn!). They also are utterly thrilled when they do beat us. The older boys still talk about how they beat me at Settlers over a year ago.
3) You will be fined for making a fuss. A card will be taken at random, or a fine will be issued, or you have to miss a turn.
4) If you start the game, you should finish it (i.e. you can't leave because you are losing).
5) The winner is congratulated with a well done from everyone. Whoever wins is also supposed to be gracious in victory.
6) The winner tidies up. I'm not sure when this began, but this is happily accepted by everyone.
It's not perfect, but clear expectations help us to have more fun together, and to enjoy being competitive while still being kind to one another.