How the hell did you end up seeing that??? That is a good question... A VERY GOOD question. I blame coworkers, work is a nice scapegoat, always.
Storyline is pretty much: Nerdy guy and hot successfull girl meets at a pub, has drunken sex unprotected, pregnancy ensures, hilarity queues up. Normally I'd roll my eyes at the mention of such a film, really. But the guy that made it also made 40 year old virgin, which was fantastic, so he gets excused.
In essence, the best movie I have seen for a long while, perhaps years. And mostly I blame it on the characters, especially the male ones. Both great script and incredibly good acting. I pretty much laughed for most of the movie (thank god there were some serious moments during it, so the laughter could die down during those sections), though it contained a lot of "get Oguleth embarrased"-sections I still managed to actually watch most of it without having to do facepalm all the time.
Hard to tell what exactly made me like it so much, I am guessing the recognisable factor. And the directness of it - most such films just end up being some kind of icky nonsensical soup where I fall asleep because it's not funny, and I get no ties to the characters of the movie. This is just the complete opposite of that, I am starting to wonder if a movie needs swearwords for me to like it, however..
Small miracle, a movie not containing at least some violence making such an impression on me...