The first thing I heard about this movie, from a friend, is that you need a PHD in nerd-speak to get all the jokes. Sure as shit.. after sitting through the movie tonight, there were so many in-jokes, and references from other sci-fi flicks, that I couldn't keep up with them.That excitement aside, the movie itself was very good.
Imagine Fanboys, mixed with a bit of Spaced, and a little Clerks thrown in the mix. If you get those references, you will absolutely LOVE Paul. If you aren't familiar with those references, then.. well.. you will still like the movie.
You got a couple of nerdy friends on a roadtrip to visit all the places of sci-fi lore in the western United States. Along the way, they meet up with an actual alien. Who, serendipitously, is able to speak fluent english, with only the minor drawl of a stoner accent. They then embark on an adventure to help Paul the Alien to get to his destination, while avoiding cops, feds, hillbillies, and bible thumping papa.

Wether you're an all out fanboy nerd, or just a minor participant of the genre, you will enjoy the flick.
Needless to say, that the writing team of Nick Frost and Simon Pegg are top-notch. They just continue to demonstrate their abilities to hone in on this niche. And I love it. We need more artists who are willing to Alienate mainstream mentality, in the aim of appeasing to a growing audience of nerds.