I loved the pairing of Robert Downey, Jr, and Zach Galifianakis. This movie was very funny from the time the two were thrown together until the end of the movie. Some moments were a little too much to watch, but other than that, I spent a lot of time laughing as the two journey to get home in time for the arrival of "Peter's" baby's birth.
Zach Galifianakis is genius with his awkward comedy, and is so very different from how I first saw him when he was on "Tru Calling" years ago.