For those who wanted to know - it isn't a secret society or anything in the nature of "Eyes Wide Shut". The one we went to is called the Velvet Curtain and it's located in a huge flat on Ervay street just off of downtown Dallas. It's a private party held once a month for couples or single women only - and you have to secure an invitation before showing up.
All in all, it was a pretty interesting night. I have to admit I was nervous going in, but it was basically a big party with dancing and drinking on the floor level and the crazy sex stuff going on in a couple of rooms on the bottom level and in the balcony. The people were pretty nice and not pushy at all, and there were some pretty hot women there - more than I thought going in. Most of the people seemed to be in the late 20's and 30's with most being white but several mixed, hispanic, and black couples as well. It's definitely a different kind of experience, but I'd do it again. Any questions feel free to ask...