I can help a little with how Curves works. I have belonged for 1 1/2 years. I go 4-5 days a week. The machines (we have 11 now, all Curves start with 8 and then can buy more (I think there are 4-6 more). The machines are set in a circle usually with a jogging platform in between each machine. For one 30 minute workout with 11 machines, we go around the circle twice plus 8 more stations. So no matter where you start in the circle you finish your workout in order. You are allowed to go around as many times as you want, and some people I know do 3 full circles. Our Curves is open 6 days a week and you can go whatever days you want, as many times as you want. You start wherever you want (or wherever there is an open station) and use the machine for 30 seconds, and then the voice on the recording says "change stations now" and you move to the jogging station next to it. There, you do whatever you want to keep your heart rate up. Some people walk in place, some jog, some dance, some do arm movements, etc. etc. Every 6 minutes or so the voice on the recording will tell you to take a 10 second heart rate, so you can see if you are keeping in the target range for your age. The people who work there go around the circuit with you the first time to teach you the machines, and will watch you for the next few weeks to be sure you are using them correctly. Once a month you can be weighed and measured (only if you want to) and they keep track of your loss for you. I really enjoy it and have met a lot of very nice women who go at the same time I go. Because these are resistance machines, I still feel I am getting a good workout even after 1 1/2 years. I find I am stronger so I can do faster and more reps in the 30 seconds I am on the machine and keep my heart rate up so I feel I am getting a good cardio workout also. Luckily I have never had to wait for a station to be open, like some posters mentioned, but I go at about 7:15 am after I drop my daughter at school. It probably gets more crowded later, but at that time there are usually only about 12 people there.
I hope this helps, and I'll try to answer any other questions you might have!
Denise