I really like this idea — a regular gathering would make it much easier for newer people to know when to turn up and say hello, rather than hoping to bump into someone.
Would it help to start small, with one fixed slot each week, say a Saturday, and see who can make it? If people shared roughly what time zone they are in, we could pick a time that works for as many as possible, and then post the time and room in the Events section each week.
I would be up for joining a first one and seeing how it goes — what day and time would suit you best?