Basically the story is about a girl and a guy who meet 10 years ago in summer camp. They keep running into each other over the years, and although you can tell the guy is totally into the girl, they just never seem to do more than run into each other.
At one point the guy gets the girl's phone number, but he is dating someone at the time, and he never ends up calling her. One year later, after he finds out his ex-girlfriend is dating/sleeping with his father (who is a washed up movie star), and he ends up sending her a text message (after texting/calling all the girls in his phone, looking for someone to have pity sex with him), and they end up getting together (although they don't have sex at first like you figured they would, but they do shortly after that).
Source -- this was I think one of my favorite parts of the movie,
but I don't want to ruin it for you, so you will just have to go see it!
They decide to become friends with benefits...sex, with no strings attached. Of course we all know this never works, and without ruining the movie, I am sure you can figure out how this is going to end.
Source -- this part, the "period scene," was a little dorky,
but the scene after that was really cute, so it made up for it.
Despite his relationship with Demi Moore, I totally fell in love with Ashton Kutcher in this movie. He looked so young, and was very cute and romantic. Of course I love Natalie Portman (although sometimes I hate her because she is so beautiful!), so it was a great combination. I totally could see the two of them together.
If you get a chance, totally check out this movie. I would love to see it again, and will probably buy it when it comes out on DVD.