Here's an example of lindy (the dance I did for four nights), demonstrated by two of my teachers, Tiff and Kenny:
Tiff and Kenny did a show-stopping dance on Thursday that inspired me to dance better on Friday. Instead of doing the same few styling moves (foot and leg movements in this case), I pulled out all the stops and did every one I could think of--and I think that doing several movements instead of repeating a few movements dozens of times was what kept my knees from hurting. My partners enjoyed the variety, too!
Another dancer and I were talking about workouts. I mentioned I had stopped doing squats a few years ago, and she said she didn't do them, either. "Unless your knees are perfectly lined up over your feet, it'll hurt your knees." Perhaps; all I know is that I feel better not doing them. For my lower-body workout, I use the DVD Ballet Conditioning. Lovely Elise Gulan, ballerina, leads viewers through a series of exercises to rival the Navy Seal Workout.
The morning after my dancing epiphany, I did a 20-minute cardio dance workout (a la Body-for-Life) without any knee pain.