I saw Year One, The Hangover and Whatever Works today.
I thought Year One was hilarious and intelligent despite the fact that many reviewers hated it. I've only laughed so hard that I cried at a few movies in my life, and Year One was one of them, but I think you would have to appreciate dark comedy to see as much humour in it as I did. The scenes dealing with the biblical Abraham were among the best.
The only reason I saw The Hangover was for comparative purposes with Year One. I expected The Hangover to be stupid and not funny, and I found it indeed to be stupid and only minimally funny. Compared to Dumb and Dumber, which was also very stupid, but was hilarious.
Whatever Works was a very solid effort, especially considering how many films Woody Allen has put out. Some familiar themes from his previous movies are evident in Whatever Works, but he gives it a genuinely unique and interesting spin to make you feel like you didn't waste your time. Best line in the movie was when Larry David was complaining about how nowadays there are different summer camps for everything that kids can attend, but he mentions the best idea would be to send kids to a mock concentration camp during the summer so their parents instill in them the value of understanding the reality of what the human species is capable of.