The really high-end resorts have "overwater bungalows" built on piers out over the shallow lagoon. They're veeeery expensive, but like lodgings nowhere else. We stayed for a few days at this one (the Sofitel at Ia Ora beach), and I sat on the sloping ladder leading from our deck down into the water and fed cracker crumbs to the fish. Hordes of brightly-colored tropical fish would swarm around my legs eating the crumbs! Another fantastic lagoon to go kayaking and snorkling in, too.