It's confusing whether Train Man is a true story or not because the characters they're based on (or not) supposedly have always remained anonymous. But it's a lot more fun to treat it as real life.
The story has spawned comics, a TV series, and movies that all have profited a great amount in Japan. It follows a nerd who has a moment of bravery and helps a woman being harassed on a train, and becoming known as Train Man on his internet chat board, he is guided by his internet companions on his journey to win over the woman of his dreams. The main character is hopeless most of the time and there are many moments you can't help sigh out loud because of his incompetence. This ain't no Tom Hanks & Meg Ryan flick.
Why you should see it: Because you know what every American romantic comedy is like, the formula is etched in stone. Throw that blueprint out the window because you're about to follow a real geek who really doesn't know what to do with what he's feeling for the girl.
And the most interesting part of the story, the material it's based on, is right here. An English translation of the chat room that chronicles his entire story.