YES! Fun AND funny. This movie is so much fun to watch, and several laugh out loud moments. Several reviews already stole my "Headline" ... "Just split the cookie!" - that line will make you laugh for a while. Galifianakis plays a bit against type here as a straight arrow family man, and understanding HR employee. John Hamm, has incredible comedic timing, ("oh Jesus Jeff"), and is a perfect humor match for this role. Both female leads are excellent comedians, and beautiful to look at. In fact the entire style of this film is really fun to watch. The chemistry between all four actors is rarely seen in an ensemble cast.
The bottom line - great film, and a pleasant surprise. John Hamm should get more comedy roles - he's really good in my opinion. I haven't read all reviews, but I think this was so much fun to watch, (still I'm sure many will disagree). If you've enjoyed films like "The Hangover" I think you will find this one amusing. Very little cursing, (I know that is important to a lot of viewers), and no nudity (just women in underwear). All in all pretty wholesome comedy that has a sophisticated feel to it.