I don't usually feel compelled to write reviews of things I don't like, but after the 'hype' that surrounded this I felt compelled! This film is quite extraordinarily charmless and unfunny - I actually gave up on it after an hour (so it may conceivably be redeemed by the world's best ending, but I doubt it).
Michael Cera, so good in Juno, should have known better, as he could have spared tarnishing his CV. Where American Pie at least had some laughs with its dollops of crudity, this film seems to think it's good enough just to make as many crass references as possible and forgets that it might be nice to actually make it funny. South Park, Team America, Farrelly brothers movies etc remember you need to actually put some good gags, engaging characters and dialogue in the script, not just an endless stream of puerile rubbish.
Quite why some film mags gave this such good reviews is beyond me - it feels like a script cooked up in 10 minutes by bored kids trying to shock. Don't waste your time.