Today is the anniversary of the rescue of the Donnor Party, according to The History Channel's This Day in History. (Put 2/19 in the upper left corner of their site if you're viewing this after Feb. 19.)
The Donnor ordeal is a tale of true-life horror that's inspired many re-tellings and spin-offs including the chilling "A Child of the Golden West" from Dennis Etchison. Read that story and you'll never look at a bottle of Mountain Dew in the same way again.
A great tool for terror writers can be found at How Stuff Works - How Voodoo Works