You may or may not have heard of them. I had not until it came up in the A.R.T. group.
You can see examples on this website: http://zentangle.com/index.php
There will be a mini class near the end of September. You can get a small kit for a reasonable price to try it out. That is what I am going to do. You can go to the A.R.T. group for more details. I don't want to spend the money for the full sized kit until I try and and find out whether I like it or not. I do think that a lot of my 6th graders would be interested in something like this. They sure do like to doodle - especially when they aren't supposed to be!
Just passing along the information. If you have done this, I would love to hear what you think about it. Please leave a message in the comment section.