doodle patterns - links through to a great site with lots of good ideas and how to draw
Betweed. Official Zentangle with variations. I love this tangle and it looks great when shaded.
Awesome border sampler by Miriam Badyrka (The Doodler) - whether she meant to do that or not ;)
http://doodles.typepad.com/thedoodler/2011/09/doo.html shapes to play with
Do you Doodle? http://MorningCoffee.CreatingCalmNetwork.com The art of the doodle on Morning Coffee on Tuesdays from Sheboygan, Wisconsin with Ann J White, Angie Ledbetter, and Kathryn Magendie on the Creating Calm Network Broadcast