Friday the 13th leaves much to hope for in the realm of the doom and dark. First of all, from a comment by epedia-ga on a question answered by the lovely Voila-GA, we learn that the fear of Friday the 13th is called Paraskavedekatriaphobia.
From Pinkfreud we learn another interesting(?!) Ft13th fact:
"Other characters came and went, but Jason's mother, Pamela Voorhees, returned over and over in flashbacks and dream scenes."
(answer to: Besides Jason, what character appears in the most Friday the 13th movies?)
And our Serenata (now I am sad :-( ) managed to find out, in which months in 1948, Ft13th occurred.
Have an horrific Friday the 13th!