The Constant Doodler draws using a continuous line.
The Work Doodler doodles while in meetings at work – similar to the way I used to doodle during class or in between orders at the restaurant.
Doodlers Anonymous is a site to join and attempt doodle contest challenges or showcase work.
Scene360 has art of all kinds from numerous artists.
John Howe makes sword-and-scorcery-style artwork and has a forum to discuss such things one can join on his website.
FromQuarksToQuasars is a blog about…well…everything.