I'm glad I don't run AdBlock in all of my browsers, as spotted this deal a few days ago.
Load up your OneSmart card with $300 (or slightly over to be safe!), register on the form and spend $300 by 28th Feb and get $50 free Airpoints.

I haven't been able to use it at many EFTPOS terminals, the tap and pay works but if I insert it in any of the machines it asks me to swipe (these don't have a magstrip on them do they?)

http://www.airnewzealand.co.nz/onesmart-register