The current movie industry seems to be engaged in an orgy of remakes to reduce the risk of funding completely new scripts. We have had a recent remake of Total Recall and are about to get a remake of Robocop. Sometimes the remakes happen very quickly (the Swedish movies Let the Right One In and The Girl With the Dragon Tattoo were both remade in English very quickly).
Some of the scripts start as books (The Big Sleep, for example), some start as plays (The Front Page was originally a stage play but was remade as a movie several times, in 1931 and 1974 as The Front Page and in 1940 as His Girl Friday) and others as screenplays (Robocop seems to have started as a screenplay).
What is the most remade story?
NB For clarity let us exclude series where a character such as James Bond repeats and stick with those where the story credit references a single play, book or original script.