I think this is so funny, I had to order one of the t-shirts. It will help me wind down from wearing Obama campaign t-shirts. Profits from the merch benefit the National Center for Science Education (NCSE), which is also cool. I noticed there that they have a new edition of a book called Evolution vs. Creationism and that you can download a PDF of chapter 1 ("Science: Truth Without Certainty") for free. It's a nice exploration of important terms like theories, laws, hypotheses, and facts, and how these terms differ between common usage and scientific usage.
Thanks to Asymptotia for the tip.