Seattle based design firm, Modern Dog, just released their 14th poster for 2009's Art Walk. Over the years these posters have become well known in the design community. They have even been collected by various museums including the Louvre. I can't even imagine the feeling as a graphic designer to have your work displayed in the Louvre.
I saw the two principles of Modern Dog speak at last year's HOW design conference in Boston and loved how down to earth and corky they were. Their work is so unique, entertaining and funky. One of their points that I still remember is to stop depending on the computer so much. Pull yourself away and start sketching with a pen and paper.
They do work for a lot of high profile clients, which is encouraging that you can still be edgy and different and work with mainstream corporate companies. Check out their work for yourself.