We recently got a new cooperative game, Flash Point. This is a game where the players work together and everyone wins or every one loses. I like these games, especially after the kids go to bed. I'm not always interested in using our few quiet minutes in competition.
In Flash Point, the game board is a map of a house, and you are the firefighters. Your goal is to save the people in the house, putting out fires as you go, before the house falls down or they get burned. I haven't tried the complicated version that includes fire hoses and ambulances. But the simple one is lots of fun. My kids enjoy the autonomy that it offers. There is less big plan working together than other cooperative games we've played. Instead it feels more like lots of little missions you help complete. (Put out the fire in the kitchen. Save the person in the bedroom.) But watch out for false alarms (look like people to save, but aren't) and explosions!
The game claims it is good for 2-6 players. Young A enjoyed playing it by himself. The Professor and I can fit one or two games after the children go to bed. The Professor has played with three or four or five of the kids. Overall, we've found Flash Point to be a versatile, enjoyable game.