Rotorua!! I've only been there once, when I was 7, but I was fascinated by the bubbling mud, lol. Other than that all I can clearly remember is a) So stinky! b) A big geyser, I think it was this one (http://en.wikipedia.org/wiki/Pohutu_Geyser), and c) Eating a corn cob that was cooked in a hot pool.