Source: http://www.vulture.com/2014/04/brief-his...

Marvel Studios has helped bring post-credits teasers to the forefront of the modern moviegoing experience. These types of scenes, though — also referred to as the stinger, the credit cookie, and the egg — have been around for several decades. Figuring out exactly when and where they began depends on your definition of the original term. If you think the post-credits sequence is a continuation of a scene while the credits begin rolling (not the strict modern interpretation, of course), then you might say 1960’s Ocean’s 11, in which Frank Sinatra, Sammy Davis Jr., and the rest of the gang are seen walking down a boulevard in Las Vegas, represents its first incarnation.