Did everyone already know about this?
I was snooping around on the Sakura of America (Microns, Gellyrolls, etc.) and in their lesson plans area I found a zentangle lesson. The link was broken so I contacted them and got the correct link.
It's aimed at kids, and I think it may be the same lesson plan that Rick and Maria have posted at their site. Still, it's exciting to see Zentangle® featured, so why not visit and let Sakura know we appreciate the lesson and would like to see more.