Mistakes
In the scene after Black and Cera become guards for the city of Sodom, they are told to line up in formation. Cera's character claims to not have a sword but when they are walking outside to line up you can see he has a sword in his scabbard. See more...
Movie Mistakes blog
Popular blog posts:
Top 15 biggest Harry Potter film mistakes
30 Biggest mistakes in the Star Wars movies
The 10 biggest mistakes in Iron Man 1 & 2
Other great sites
Year One (2009) - 3 quotes
Directed by Harold Ramis, starring Jack Black, Michael Cera, Oliver Platt, Olivia Wilde (add more)
Zed: I'm sorry. I wasn't listening. All my brain blood was in my boner.