I generally excuse poor losers from whatever game we are playing next (and I usually plan it by design that we play two games in a row). I tell the poor sport that if he cannot play nicely with his sister/friends/me then we do not want to play with him.

I have the same issue with the 5 year old I watch. I usually excuse her to her room after 1 warning about being polite. Mostly its just a stage and its an unpleasant one.

I babysit a two year old and a seven year old during the summer. The seven year old is a very sore loser. I tell her that if she will not play nicely then she can't play. She promises to play nicely and then goes straight back to her old ways. Whenever she loses it's all about how "the game is stupid" or "everyone else is a cheater". Any strategies to work with her? Thanks everyone!