Whitianga Bike Park has about 10km of singletrack in bush about 2km from downtown. The trails range from easy to extreme. Some are clay; others are shell covered. There's a "Skill Zone" with elevated board ramps and a see-saw. There is also little pump track and a BMX track with some serious humps.
The park is well set up for a day out with friends and family with a BBQ area and a toilet. For non-riders there are some walking tracks including one that goes up through the bush to some fine young kauri trees.
So if you're heading to Whitianga for some summer fun be sure to take your bike. The local club knows about some other rides you'll enjoy too.