I'm not talking about movies about the same thing, or even with the same character...no, just movies with similar tiles.
And so, I begin the "Similar Name, Not the Same Series" with...
Avatar: The Last Airbender (2010): Human civilization is divided into four kingdoms: Earth, Wind, Fire, and Water. The fire kingdom is bad, and only one human is left from the air kingdom can unite them all.
Common Theme: Even though they both have love stories, they still probably make bad date movies.
Not the same: James Cameron's Avatar will be viewed as a sci-fi success, M. Night Shymalan's The Last Airbender seems like it's positioned only to engage fans of the TV show.
Other movies in the Similar Name, Not the Same Series:
* 9 and Nine
* Up & Up in the Air
* A Single Man & A Serious Man