the hypobaric chamber
The first day, today for me, they put you into a pressure chamber and take it up to 5000m of pressure (about twice the altitude of Aspen, so I hoped I could ace it) and watch you for 30 minutes. They also put you in a bathrobe to keep warm - quite photogenic, eh? Underneath I'm full of wires.
The second day, they do it up to 10,000 meters...
photos courtesy of Marsel Gubaydullin