For their wedding--their Big Damn Wedding--Flickr member bittenby and her husband dressed as Captain Mal Reynolds and Inara Serra from Firefly. The ceremony was conducted in front the TARDIS by Princess Leia. Yes, really! You can view more photos at the link.
UPDATE 4/18/13: Commenter Megan Finley directs our attention to Offbeat Bride's post on the subject. If you don't already read Offbeat Bride, you should start.