The most tricky thing with in-person meet ups is that people are really busy, particularly those of us who do volunteer activism on top of paid work (or in my case instead of ;) If there are lots of meet-ups on narrow topic areas (one for CC, one for open goverment, one for open street map, one for each open source project or language that exists etc etc), they will all struggle to get and maintain critical mass. What I'm thinking is that a meet-up which unites all these sectors under the NZ Commons banner, as I hope the website will, and is promoted as an extension of the networking on the website, could be more successful.
If I remember correctly, the approach that's been taken with CC meet-ups so far is to make them a fairly social event, along the lines of the meet-ups held at a cafe/bar on a regular schedule people can remember (eg first Thursday of every month starting at 7pm). One problem is that a lot of people are doing these now, in Ōtepoti we have monthly drinks for the Dunedin LUG, CodeCrafters, Greens Drinks etc. In Welly you have lots more. As well as competing with all these, this approach can become exclusive of those who can't afford to buy drinks and food at cafe/bar prices every week, or just don't want to attend group drinking sessions that often.
Another approach is to hold the meet-up in some sort of community space and make it a bit more structured. Have a specific topic or issue to focus on each time, and maybe screen a short documentary or circulate information about a project beforehand, to frame the discussion. We held a series of three doco screenings last year on surveillance (Disintermedia, and Free Culture Otago, in partnership with a campus radical group called Organisation for Global Non-Violent Action). After a bit of false start, we managed to get a handful of people to come along regularly and participate in some good discussions.
Another approach might for the meet-up to be a sort of brainstorming session, with specific goals or outcomes somebody wants to achieve, which either require or could be assisted by cross-sectoral cooperation. The discussions on the NZ Commons website may end up inadvertently revealing stumbling blocks (whether technical, social, economic, political etc) which are limiting the development or interoperability of commons, and an open brainstorm meet-up could then focus on how to overcome them. Back before Wikipedia was CC licensed, the problem of how to create synergy between CC and Wikipedia could have been the subject of a brainstorming meet-up.
The last approach I want to mention, works for those who want 'less hui more do-i'. Some kind of practical workshop with a libre bent. As an example of this, Abe and I intend to organise some workshops to build Freedom Towers (as created by the Free Network Foundation for Occupy Wall St), so we can provide free wireless access to local servers full of CC licensed media, distros of GNU/Linux etc. Eventually we hope to get enough Freedom Towers in place to establish a wireless community network around Ōtepoti.
Any or all of these styles of meet-up could be organised as part of the NZ Commons project, but they're not something Matt can really push from HQ. They need 2-3 local Mentors willing to co-ordinate, and do the work on the ground to get people coming. If people are keen to do that work though, it really helps to have a formal endorsement from HQ, that this is indeed an NZ Commons event, and some help with promotion (mentions on the website, Twitter etc).