10,000-strong ride down under

The kiwis know all about extreme sports, being the inventors of jumping off bridges for fun, rolling down hills in inflatable balls, etc. When they get on their bikes, the extremities come in two forms. First, the hills: an unfeasibly large part of New Zealand is outrageously hilly. To someone like me, used to the relatively gentle rolling slopes of Northumberland, it might as well be the Pyrenees. Second, the sheer numbers of people riding them. Yesterday's Lake Taupo Cycle Challenge course profile (go on, check the link) is fairly typical of the sort of terrain you need to traverse round these parts. How many countries in the world would find that sort of event attracting over ten thousand riders of all ages, let alone find enough combatants keen enough to contest the four-lap, 640km super-enduro version? Answers on a postage stamp...