I'm taking two Zentangle classes at MQX this coming April with Pat Ferguson. I have bought some books and started doing the drawn tangles, and Mrs. B is correct, it is totally addictive. I've always been a doodle-er so this is a reallly great thing to me. I have yet to try quilting the tangles but that's what I'm going to the class to learn.
It is a very, very relaxing art form also. I'm taking care of my Mom who has advanced cancer, and I find myself sitting down to tangle every night so that I can relax before going to bed. It really does help. It keeps your mind occupied but yet your mind is not racing.... very strange but it's true.