I hope I don't get any flack for putting good cause in quotes: I don't mean to suggest it isn't a good cause, merely that me buying myself an awesome shirt would be more selfish than altruistic.
The proceeds from these shirts, based on multiple fandoms, go towards the "FckH8" campaign to fight Proposition 8 (for those of you living under a rock, that is an anti-gay-marriage campaign). I just love them. When I scrolled over the design I got a close-up of the text, so just trust me that these are shirts.
Some Time Agents Marry Office Boys
Some Doctors Marry Big Blue Boxes
Some Doctors Marry Romans and Gingers