The Facebook pages Weird Facts and WTF recently posted this image.
Exposure to cold makes body fat easier to burn. Scientists found that putting ice packs on problem areas can burn extra calories. Combine that with 10 minutes of shivering, which burns as many calories as an hour's exercise, and you could literally freeze your butt off.
I'm not so skeptical that shivering does burn calories, but is it really the case that the mere application of cold will burn more calories?