Friday, Oct. 3, may be the date of Taylor Swift’s highly anticipated “Life of a Showgirl” album release, but it’s already a very important day in the pop culture world for another reason entirely.

The mean girls are hoping to raise money for a good cause. It’s Oct. 3, also known as ‘Mean Girls’ Day for the legion of film's fans. And the cast of the hit comedy is marking the occasion by banding ...