I assume this means literally everyone, non-gamers included? If so then I think that The Sims is the way to go. It appeals to everyone on some level and it’s strangely addictive. You can have the Sims do whatever you want, build whatever you want, etc etc. Plus there are so many funny stories around of what people have done with their game (one of my particular favourites is someone that had their swim drown then made all the guests show up to the funeral in swimwear). I find that almost everyone, non-gamers and gamers alike have played The Sims at some point and it’s often a nice starting point in a gaming-based conversation.
Have you got any funny Sims stories? Which game do you think everyone should play?