I just saw this trailer for it and it seems like ILE - SEI duality. The girl seems really PoLR (she doesn't care about her's or anyone else's feelings, at least initially) and the guy (wasn't the kid from 3rd Rock from the Sun?) really reminds me of Kamajama.
[ame="http://www.youtube.com/watch?v=PsD0NpFSADM"]YouTube - 500 Days of Summer - Official Full Length Trailer[/ame]
[ame="http://www.youtube.com/watch?v=KLe399FeWM4&feature=related"]YouTube- (500) Days of Summer - Boy Meets Girl[/ame]
[ame="http://www.youtube.com/watch?v=rZJ5iYERJlA&feature=related"]YouTube- Zooey Deschanel and Joseph Gordon-Levitt - (500) Days Of Summer[/ame]
Also if anyone would like to fill me on whether it's a good movie or just a sappy love story, that would be great, so I can decide whether I should see it.