[epe]

The clearest explanation I've ever seen of this method is here:

http://www.evanmiller.org/rank-hotness-with-newtons-law-of-c...

[mindcrime]

Heh, yeah, I think that's the same page I originally used to come up with an approach to doing this. There are also some discussions of this same topic on StackExchange and some other sites.