Fail Whale T-Shirt
The Fail Whale, designed by Lu Yiying, was made famous by Twitter, which shows it whenever the server is overloaded or down. Zazzle and Spreadshirt are the two official places to buy the Fail Whale t-shirt, and I've ordered mine.
Zazzle
Zazzle, an online marketplace for custom print-on-demand products like T-shirts, mugs, and other personalized merchandise.