Wim Hof makes money doing extreme endurance, mostly related to cold.
He believes that some moderate cold training is good for people because changes of temperature make the blood vessels more flexible, though he pursues extreme endurance because he's fascinated by it..
As in Joshua Blaine's original description (below), but may be used to brag about things you've accomplished either this month (December) or the previous one (November), assuming that you haven't brought it up in any earlier Monthly Bragging Thread.