"Cooperative games emphasize participation, challenge, and fun rather than defeating someone. Cooperative games emphasize play rather than competition. Cooperative games are not new. Some of the classic games we participated in as children areclassic because of the play emphasis. There may be competition involved, but the outcome of the competition is not losing and sitting out the rest of the game. Instead, it may involve switching teams so that everyone ends up on the winning team." - a guide to co-operative games for social change

Co-operative board games here. Gamespots top 10 co-op games here. And a piece on the Educational Value of Cooperative Games