It's a fitness program that combines aerobic circuit and weight resistance training. It takes about 40 minutes, and they recommend a minimum of three times a week. I've been trying to go five time a week.
It's hard for me to explain the concept: there are about 18 "stations", and you only spend 35-45 seconds on each station, and you do three "laps" or "circuits", then have a cool-down, stretching process. You start out on a jogging pad where you warm up, then proceed alternately with jogging pads to various resistance machines geared to different parts of your body. Most of the resistance machines are great: one of them has helped me tremendously with neck and shoulder pain. THere are a couple of resistance machines, however, that I think could have been used during the Inquisition ;-)
They have a website: www.curvesforwomen.com which will tell you where the locations are. They don't advertise on TV - only in newspapers. They'll give you a freebie trial if you're interested. What I like is that it's only women, and most of the women in the one I go to are not 20 year-old hardbodies, they are real women, all ages (one lady is in her 70's), shapes, and sizes.