I went snow caving once with my wife's family. We were dating at the time so I had to look cool and wear my contacts. I have to wear the gas permeable, and you can't sleep in them. So when we went to sleep in the snow cave, I popped my contacts out and put them in their case. It was ten below zero that night. The next morning I had to put them suckers in my eyeball at -10 degrees. Could easily be one of the most painfull experiences of my life. How many people can say they've had a contact frozen to their eyeball. The second one was even worse, I knew what was coming.