I really like this idea via Top Lead Generators: Good Idea From My Local Jamba Juice

Up on the wall, there was a giant map of Bakersfield with hundreds of little pins scattered all over the map. Below the map was the message, "Tell us where you live so that we can put a Jamba Juice in your neighborhood".

That's smart, on a couple of fronts:

It's fun, non-intrusive and interesting for patients.
You get valuable feedback on where your patients are coming from. (I'd guess you'll see clusters develop.)
It reinforces your value to the patient. They can see that (hopefully hundreds or thousands) of others have made the choice to come to your medspa.
It can provide valuable info that could be used for direct mailings or PR stories.

Sales leads don't always have to come from a list. Valuable information is yours for the taking if you give your customers a chance to have a little fun and take a second to provide you with information you can use to grow your business.