I've been fortunate to meet other members on the site in Vancouver, Montreal and NYC, and I know other meetups have happened. I wondered if perhaps a community-wiki type list by continent and city for anyone who would be keen to meet for a coffee would be a useful idea? You may be passing through a city and have no idea user X lives there, who could show you around or give you a great tip.
I thought I'd create an answer and people can edit the answer, rather than have a thousand teeny unordered answers.
As for contacting, I guess an @tag is handy, but the chat is another good go to place to organise.