Rick-
this isn't what John Moore had in mind, but twice I've used the winter time to totally revamp my swing -- but only in my head! That is, I don't swing a club, I don't exercise, I just read a lot of instructional books and then imagine myself with a new swing. (It works especially well if you're lying on a couch, half asleep). The first time I revamped my swing to be more like Ben Hogan's, but when spring came I found out that, unfortunately, it didn't work so well for me. (I really wanted to swing like Ben Hogan, but without finding it in the dirt!) BUT the second time, last winter, I revamped it again by imagining I was Greg Norman...so I imagined myself standing more upright, and having a steeper swing plane, and finishing high...and you know what? I had a pretty good summer, and the best round I've had in years. (Though, it didn't quite come out like Greg Norman - more like Vijay Singh's old swing I think. Actually, it was more like Chris DiMarco's swing...).
Like I say, nothing a PGA professional would recommend...
Peter