The link to the right, Rasmussen Daily Dem Tracking Poll, now takes you to a modified version of the daily Rasmussen numbers. I dropped the All Others numbers and added trend lines for the three top dogs.
I tried various types of trend lines available in Excel and, like any self-respecting, serious researcher, chose the one that gave me the results I wanted. That turned out to be a fifth-order polynomial fit. Check it out; it looks great.
Of course, the problem with fitting a curve to such data is that there's no underlying physical process which we're trying to get at. Or if there is, no one but Hari Seldon knows how to model it. But, what the Hell, so long as the curve looks good, I'll leave it there.