Where to start...
I've been to about the last five of these. Magic affairs, which never go to plan.
This year, the event runs from Thu 21st to Sun 24th March.
More here: http://www.nzballoons.co.nz/
Some details are still to be confirmed, but essentially there is an event at dawn and dusk or thereabouts, each day. Some events actually involve the balloons lifting off, and some don't. All of them are great fun to photograph. It's not uncommon for only half of the events to actually happen, dependent almost entirely on the weather.
People often just show up for one day, as well.
While I'd be more than happy to gather people together for this, and make sure everyone knows what to expect and so on, I think each person (or small group) should make their own arrangements for each event. Waiting for stragglers guarantees missing the important few minutes.
However, there are also large chunks of time between the events, and we could arrange to do other things (cafe, Castlepoint, cafe, pub, gardens, cafe, pub, cafe etc. )
Accommodation is very hard to get in and around Masterton if you leave it too long to get organised, so if you plan to go, let's get some numbers together early. Are you with me?