Awesome exhibit of work from poster designer/propagandist Shepard Fairey going on right now at the Boston Institute of Contemporary Art. Even if you're not familiar with his overall body of work, I'm sure you've seen his Obama campaign poster. Here's the NYtimes article. Check out his website: obeygiant.com.
Disclaimer: these images don't even give you a moderately complete overview of all that he's done creatively over the past decade. Definitely check him out.