I was pretty jazzed about this movie, since I loved the book when it came out. Of course, the movie's plot only barely follow's that of the book, and there are more than a few changes to each character as well. However, I think the feeling of the book was captured well here, and that was what I enjoyed the most.
Michael Cera is pretty much Michael Cera here, but he's more Arrested Development-era Cera (heh) than Extreme Movie Cera, thank all that is holy. Zach Galifianakis is boring as usual- he never seems sure if he should be the straight man or over the top, and instead he teeters in the middle and fails to create characters. His slack is picked up by Ray Liotta, of all people, and Portia Doubleday and her Saunders family members are hilarious and leave you wanting more after each of their scenes. Fred Willard, in a rare performance, lays low in most of the film, but steals scenes even from Cera when he speaks up.
As far as events are concerned, this movie is rated R for multiple reasons. Nick's Fight Club-esq alter ego Francois is into blowing ish up, and he does it really well. Nick, on the other hand, is pretty much just good at being awkward, masturbating, and trying to get Sheeni to do it for him. Justin Long's character brings the drug content full force. Overall, there are enough WTF moments to make me think there should be a "Don't Try This At Home" warning on both sides of the film, and I would never recommend this as a movie for kids, or as a movie for parents to watch with their offspring of any age. Do watch it though, and glory in your lost youth as I did.