Hello, Pop!, a 17-minute short made for MGM in 1933 featuring the Stooges alongside their creator, Ted Healy, has been rediscovered in a garden shed in Australia.
http://www.theguardian.com/film/2013/sep/30/three-stooges-film-discovered-australia-garden-shed
Film historian Fernando Pena has discovered an alternate version of the classic Buster Keaton short The Blacksmith, featuring numerous never-before-seen gags and a new ending.
http://www.youtube.com/watch?v=biJ15ixRp9U
http://flavorwire.com/404585/17-amazing-stories-of-lost-and-found-films/
Other rediscovered films
http://flavorwire.com/404585/17-amazing-stories-of-lost-and-found-films/
http://en.wikipedia.org/wiki/Lost_history
http://en.wikipedia.org/wiki/Lost_film
http://en.wikipedia.org/wiki/List_of_incomplete_or_partially_lost_films
http://en.wikipedia.org/wiki/List_of_films_cut_over_the_director%27s_opposition
http://en.wikipedia.org/wiki/List_of_rediscovered_films