About two years ago there was a Stack Overflow meet up. We also had on in 2012. There has not really been much since, as far as I know. However, we used a site called MeetUp, which is still active and shows users that were signed up in the area. I'm sure if enough people showed some interest in doing another day like this, it could get more official support from Meta Stack Overflow.
I think it would be cool anyway, it's not overly difficult to setup, besides trying to find a good location.
