I ran some sprints tonight at kung fu, and my feet were getting really hot (especially when stopping). Afterwards, I was thinking about it, and- wouldn't it be cool if there were shoes with some kind of chemicals in the soles that, when jolted a certain way, would undergo an endothermic reaction and cool down your feet? That would be like so awesome! Well, that's my opinion anyway... maybe I just need to tie my shoes tighter, haha... yea, I guess that'd reduce friction.