The Fourth Doctor is particularly famous for his ridiculously long scarf, which resulted from a miscommunication between costume designer James Acheson and the knitter hired to produce it; Acheson never specified a length, and bought far too much yarn, so the knitter just kept going until it was all used up.
You might know all about the show, but what do you know of the men who played the Doctor? If you want to increase your knowledge of the subject, then don't miss this great Mental Floss article filled with fascinating trivia on the actors and the show. Personally, I didn't know the story of how Tom Baker's scarf was born:
Any of you Whovians learn something new from the article?