Chris has been posting an illustration a day for nearly 4 years. I just started following him a month ago, but so far it's been fascinating to see what he comes up with. What a good way to keep your skills sharp, too, don't you think? His topics are quite broad, ranging from Mad Men quotes and politics, to bicycles and random doodles, but they always end up being pretty interesting illustrations.
Chris has also just finished a book of his first 1000 daily illustrations, and he also sells prints on Society6 (which is how I first heard of Society6 myself). Some artists/designers that I've seen seem to have this idea that doodles and fun stuff have no place in the marketplace, opting to only try selling their "serious work", but Chris seems to take the opposite approach. I really admire him for not taking himself too seriously; it really allows his natural style to shine through!
What I like most about Chris' illustrations is that they seem to be mainly (exclusively?) hand-drawn. If I had to take a guess, I'd say he's probably using a Wacom tablet, which is pretty much the standard for graphic design tablets (are there any other brands out there?). Anyway, I would LOVE to have a Wacom tablet and learn to incorporate hand-drawn techniques into my illustrations. I've experimented a little bit with them at school and it's pretty fun.