In one of the articles in the new Windswept there is a description of the "300 Club" at the Amundsen-Scott South Pole Station and a comparison to the Century Club on Mount Washington. As hard as the Century Club is to comprehend the 300 Club appears totally insane. Basically it involves going into a 200F sauna on a day that is -100F and then running around the pole (yes, the South Pole) wearing only boots.
Here's a couple of links:
Any members of the Century Club here have any inclination to try this?