The New Zealand Open
Did you see the movies? If so then this is a fun day trip, 2 hours from Auckland. Highly recommended! You should book in advance!
Near Hobbiton, this is an afternoon walk and boat ride through spectacular caves. You can do this and Hobbiton in one day. Again booking is advised.
Fancy 7 hours of hard walking over a mountain in one day. Then this is for you!
Sounds silly but I recommend this, they actually put on a great show. About 1 hour north of Auckland.