Climb Mount Doom! (Tongariro Crossing)
The most popular hike in New Zealand; 19.4 km and 6-8 hours of Mordor volcanic awesomeness.
The easiest way to get there is by booking a return shuttle that drops you at Mangetepopo in the morning and picks you up at Ketetahi in the afternoon.
Don't forget to check the weather, take appropriate clothing and plenty of water.. Experience New Zealand like a local and have fun in undefined with like-minded people.