Interestingly enough, I came across some research articles a few years back that said one of the easiest (and one of the more effective) ways of helping to regulate body temp was located in a person's hands.
They found that if a person had been in the heat and working for a bit to the point where their core temp was going up, putting the hands in cool or cold water for 5-10 min was a good way to get their core temp to go back down. Some sports physiologists have endorsed this method as well.
So, next time you start to get overheated, simply soak your hands in some cool to cold water for a few minutes, and watch how fast you start to cool down. I've tried it, and it works!
Some have said that cooling the feet like that works as well, but when I'm working, I don't have time to take off my shoes and socks, but I always have time to soak my hands for a few minutes.