A friend informs me that the Society for Neuroscience is giving away Brain Facts, either as a downloadable PDF, or as a 52-page printed book, which they will mail to you free of charge (!) for single copies. Many funny/cheesy high-school-textbook-ish illustrations (check out the ones for "pain" and "the stress reaction", pages 17 and 26 respectively), and text written at a level suitable for educated laypeople.
I only wish it were licensed under a Creative Commons license, rather than an "all rights reserved" copyright. Maybe we should start an email campaign. I've already sent a suggestion using this form, but you can also email info (at) sfn (dot) org.