My husband and I chose to do a Canyoning Queenstown trip on our honeymoon. We took a scenic drive along the shores of Lake Wakatipu passing through Glenorchy and into Mount Aspiring National Park's Routeburn Valley, not far from where some scenes from Lord of the Rings were filmed. As an introduction to the ice cold water, we all rode down a natural rock slide into a pool of snow runoff. It completely takes your breath away it's so dang cold. It's a little jarring knowing we'd be cruising down a that same temperature river canyon the whole trip down. 

Routeburn Canyon has waterfalls, natural water slides and deep, crystal clear pools of glacier runoff. We were able to rappel, hike, climb, jump into pools, and slide down natural rock slides. It was exhilarating being in rushing waters the whole time, sporting neoprene from head to toe. I recommend going on this adventure if as long as don't mind submerging yourself in freezing waters! I could barely feel my body.