OhSnap said:
...Dance Dance Revolution.
What could be more fun?
aside from the fact that it would be dificult to bring the whole (or even any bigger part) community toghether irl for that:
all these probably unexercised geeks playing ddr together... are u nuts?!?! can you imagine the amount of sweat that would be produced?! and the smell!! we would all suffocate in our own bodily odors!
OT: considering the ammount of people in the community and all the different kinds of tastes in games I don't think picking one is possible, the most likely to success would be populistic games like WoW or perhaps Minecraft.