Drupal t-shirts and other merchandise
Drupal does not have any official merchandise; however since the Druplicon logo is licensed under the GNU GPL some people have taken it upon themselves to make their own.
Profits should be donated back to the Drupal project, Cafe Press does take a significant portion of the price. If you have printable iron on transfers handy consider grabbing a high resolution Druplicon and making a donation.
Basic Druplicon
Designed by Michael Angeles
High resolution versions are availiable.
Two merchandise shops that promote Open Source projects. 100% of the profit will go to those specific developers.
US shop: http://revelinuxgear.spreadshirt.com
EU shop: http://revelinuxgear.spreadshirt.net
Drupalicon Plush
There is also a funny plush available at FreakyToy:
http://www.freakytoy.es/2008/04/pulse-sobre-la-imgen-para-ampliar.html
DrupalWarehouse.com
Lots of Drupal merchandise can be found at http://DrupalWarehouse.com
Currently the site has 50+ Drupal specific items including beer & coffee mugs, shirts, bags, aprons, buttons, stickers, postcards, stamps, hats, ornaments, sculptures, and more. There is also Drupalcon specific items for the upcoming Szeged 2008 conference and some items of past conferences.
Proceeds go to the Drupal Association.