From the website:
Clear your schedule, you’ve got plans. Spark Broadband now comes with a side of top TV. Get hundreds of ad-free shows with Lightbox and watch what you actually want to watch. Some of the world’s best TV – on us!
If you're already a Spark broadband customer just follow the deal link to get your free voucher and get started immediately. If you already have Lightbox get the voucher and apply it to your account online. No more bills.
To become a broadband customer just visit: www.spark.co.nz
Would go well with the Chromecast 2.0 deal: https://www.cheapies.nz/node/6509
you also need to add a credit card to a lightbox account(and cancee the recurring billing option), might pay to add to the OP as it's a deal breaker for some