It's usually nice to have sidekicks XD
We don't regularly do stuff like that at work, mostly because most of us are casuals that work after hours (the office staff are there during normal office hours). Our rough equivalent would be the daily smoko meetings (a few members of the various teams smoke which obviously has to happen outside away from the building and those of us that are there will usually cluster around for a chat which could be work related or could be whatever).
I think a monthly breakfast or lunch sounds pretty cool especially if you're working somewhere full time. Are the people that don't like it introverts and/or heavy compartmentalisers by any chance? :)