It is Thousand Trails (www.1000trails.com) The reason they call is to offer a free 4 day/3 night RV camping getaway to check out their RV  campgrounds.  You may have signed up for the offer at an RV dealer or RV show, so that is why they are calling.  If you signed up for it, then the Do Not Call list does not take effect.  They don't usually leave messages, but that is a good thing, right?
I actually went with my family, attended their pitch, and got a $75 Walmart gift card out of the deal.  Had a good time.  They are a legitimate company.  If you don't want any calls, just answer the phone and ask them to kindly remove you from the list and I am sure they will comply.

I got calls from them often, I am a camper.

We are also receiving calls from 214-618-7200.  We do not answer and they do not leave a message on our answer phone.  We are also on the do not call list.

Quit calling me!!!!

This is a number from Thousand Trail membership campground. They call me a lot recently. I am in camping, so it explain why they have my number. I have my cell phone silent when a number come in that is not in my address book.

Called twice in a row.  Leave no message.  I am reporting them to the Do Not Call list.  I agree with Doll Maker..not sure it's helping much!

This company called my home phone at about 9PM.  I let the call go to Voice Mail.  They left no message.  Found out this is some sort of Resort sales company.  I have reported them to the Do Not Call list.  I signed up on this thing a couple of years ago.  Not sure that it's doing much good.

Resort Company