Anyone that does any serious camping has heard of heating up rocks and placing them at the bottom of your sleeping bag to help keep you warm while cold weather tenting.  One aspect a person I use to know apparently didn’t hear about was that of wrapping the rocks up and wearing socks, since he did neither.  While they did warm his feet up, it also burned them.  Research would be the key here, since none was performed.  I guess if we were at my Cabin In The Woods, they wouldn’t have needed the extra heat.