Zentangle.com is a great site and they have an e-newsletter you can sign up for. They have classes to become a certified Zentangle teacher (CZT), and they sell Zentangle tiles. I carry a small artist pad and Pigma pens with me and if I am waiting somewhere, I will pull them out and doodle. One of the quilt guilds I belong to had a CZT come and give a demonstration / class, and it was a lot of fun.