Enrico Casarosa is a storyboard artist for Pixar. He is also a character designer and comics artist. You can browse through his portfolio which includes sketches, character designs, backgrounds, storyboards, figure drawing and comics. He has a webcomic called Haiku 5-7-5.
At one point, after a “pubcrawl” with some friends, he got a notion put together his sketching stuff and devote a day to a “SketchCrawl”, spending the day wandering around San Francisco sketching until he ran out of day. (Here’s his description of coming up with the idea.) The results of his day of sketching are posted here.
He liked the experience so much he repeated it and collected the drawings as a book. He then expanded the idea to organized “Worldwide SketchCrawls”, inviting other artists to join in on a particular day and “sketch till you crawl”. He created a site devoted to the SketchCrawls that features bulletin boards for discussing the events and planning new ones. What a great idea.
Enrico also has a new blog, often devoted to the SketchCrawls.