Getting into hot water
Who needs to pay for a spa treatment when Mother Nature provides her own for free? New Zealand is full of hot mineral springs and ingenious Kiwis have harnessed them for maximum enjoyment. Fresh from the source, the water is much too hot to the touch, but after running down the side of a mountain, the water cools down a bit to jacuzzi temp. That's where they stick a pipe in the spring, attach it to a large plexiglass tub, and build a deck so people can enjoy a mineral bath au naturel. A few meters downs there's a cold, glacier-fed mountain stream so you can cool off.
The stream also happens to be lined with skin-sloughing pumice stones, so you can give youself the full spa treatment without paying a cent.