[eluser]BrianDHall[/eluser]
I actually don't know of any system that does this - as far as I know it is a universal weakness of so constructed rating systems.
The only rating system I know that doesn't work this way would be a +/- system, where you can rate something -2, -1, 1, or 2. Then you just tally up the points and the one with the most points in a given time period shows up top, and the user can select by "votes this week", by the month, alltime, etc. Or a system that is just vote number based works about the same.
In both of these cases though the preference is given to popularity more than anything else.
Now, as a note some sites handle this by requiring at least X votes before you actually get a star rating. With a large system this helps a lot, as if you need 10 unique votes just to get a star rating then things are quite a bit more fair.