New Zealand, Taupo

If you're driving from Rotorua, stop at the Huka falls just before Taupo.
We didn't do it but have heard from others that the Taupo skydive is one of the cheapest in New Zealand and if you go high enough you can see the sea on both sides of North Island.
If you have a day, definately walk the Tongariro Crossing if you have the energy for 7-8 hours of walking. It's apparently the best one-day hike in the country. We were short of time and so walked along it for as long as we had time and then turned back. Lots of the scenes in Lord of the Rings of Mordor and Mount Doom (Mount Ngaruahoe) were filmed in the area.