Curves is a circuit-type exercise program. The one I go to has nine different pieces of equipment, but I think the number can vary from 8 to 12 pieces. The equipment is set up in a large circle in the room, with a cardio pad in between each piece of equipment.
You start out on a cardio pad and do whatever you want for 30 seconds. There is a signal to change stations. You then do 30 seconds on one of the pieces of equipment. After 30 seconds there you change again. You do this until you complete the circuit 3 times, then spend a few minutes stretching. That's it!
They recommend that you go at least three times a week, although you can go more often if you want to.
BTW, the equipment is all hydraulic -- it's not like Nautilus or anything else. So, you are working your muscles when you move in both directions. (I'm sure there's a better way to explain that, but I can't think of one right now, LOL!) Also, the equipment is set up so that you do not have two upper body pieces of equipment in a row, or two lower body pieces of equipment in a row, so that you have time to let your muscles recover before exercising them again.
I hope this made some sense to you. I think all Curves locations let you try it out for a week free, so you can see if it's for you or not. Also, if the location is just opening now, I'm sure they will be running some membership specials!
BTW, I love it! I still do my treadmill for calorie-burning, but this is a great and easy way to tone!