Speaking of Lego games, have you two tried the Lego Star Wars games? My girlfriend and I play that sometimes. I don't know how Lego Batman works, but in Star Wars you can play 2 players simultaneously and cooperatively. Great fun. But as far as PC games go, cooperative, family-friendly games are rare anymore. As mentioned, the Wii has quite a few that fit this category, but that would mean buying a whole new thing and I don't know how crazy you (or your wife) would be about that.