One of the most important things to know about New Zealand is this: you can't sue.
It's not quite as cut-and-dried as that, but it is true the country essentially outlawed personal injury lawsuits. Instead, the government pays all medical bills in the case of any accident.
This is important, especially for the tourists. Not because I care one way or the other about my ability to file a lawsuit. Because it means operators can offer crazy experiences without having to worry about crazy insurance premiums or lawsuits.
Case in point: over three days in Rotorua, I rolled down a large hill inside a plastic ball filled with water; drove a sprint car around a tiny concrete track, and rode down a white-water river with only a piece of hard plastic the size of a boogie board for protection and flotation.

Zorbing - rolling down the hill in a rubber ball - is a surreal experience. My ball was clouded milky white, so I couldn't see what was happening. I wasn't the only one in the ball, either - my friend Paul was also enclosed, as well as a few gallons of warm water. Once the ball started rolling, we just ended up sprawling on the floor, watching the sides zip around as the ball rolled down the hill.
Sledging - whitewater rafting without a raft - is a tiring experience. Actually going through the whitewater and rapids is the easiest bit. The tiring part is trying to kick against the current to get to the side of the river or steer along.
Driving the sprint car - a souped-up roll cage on tires - was also tiring, mostly due to the lack of power steering. It was also slightly disappointing, since my best lap time was 12.98 seconds, behind the 12.6 seconds Paul managed and well behind the 11.05 course record (it was on the upper end of the day's best runs though, and at least I cracked 13). More fun was having the power to drift around the corners, hearing the tires squeal. It might not lead to the best time, but it is more fun.

Since arriving in New Zealand I've swam with dolphins, jumped out of a plane, tubed down a stream inside a glow-worm cave, zorbed, sledged, driven a sprint car, kayaked in a fiord during a downpour, kayaked in the Bay of Islands during a perfect day of sunshine, skied on a volcano, sledded down sand dunes.
Next up on the list: a bungy jump.