What long, strange careers Robert Downey Jr., Zach Galifianakis and Todd Phillips have had that led them to converge in Due Date. Phillips, in particular, has traveled a unique route from uncompromisingly punk rock documentaries (specifically Hated, about the vile punk rocker G.G. Allin) to shamelessly populist comedies (chief among them Road Trip, Old School, and Starsky & Hutch).

Recently Phillips let his freak flag fly in The Hangover, a no-holds-barred comedy about four friends who get in big trouble after a bachelor party in Las Vegas. There was a subversive edge to The Hangover that was largely missing in Phillips' other feature work, and this subversion is taken even further in Due Date.

Galifianakis essentially reprises his character from The Hangover: an obnoxious, socially inept, but essentially sweet and sad person. The limits of one's ability to spend time with this character are tested when he comes into contact with Peter Highman (Downey Jr.).

A fateful meeting on an airplane results in Peter and Ethan (Galifianakis) being ejected from the plane and placed on the "No Fly" list. Lacking his wallet, and needing to get back to Los Angeles in time to see the birth of his child, Peter is forced to travel cross-country with the intolerable Ethan, who is able to rent a car.

So begins a road movie/buddy picture that features a handful of legitimately hilarious moments unfortunately wrapped in a formulaic screenplay. Points should be given to Due Date for having the balls to not only make Ethan a believably difficult person to be around, but for making Peter believably angry and amoral in how he deals with Ethan. Pessimistic and unendingly sarcastic, Peter works well against the infuriatingly optimistic Ethan.

What worries me, after seeing Due Date, is that, as wonderful an actor as Zach Galifianakis is proving to be, his talents are still being restrained. With news that The Hangover 2 is on its way, I am becoming concerned this is the only character Galifianakis will ever be allowed to play. And, seeing as how both Due Date and The Hangover feature odd masturbation gags involving Galifianakis' character (humor that is far removed from his standup), I wonder how he feels about getting pigeonholed in that role.

I suppose what eventually keeps Due Date from being a complete success is the repetitive nature of its story. Sure, there's only so much you can do with two people driving around in a car, but perhaps that's an excuse to tighten up the running time. As an audience, we needn't see so many scenes of Peter finally starting to like Ethan before hating him again. And liking him again. And hating him again.  

I am convinced there are enough big laughs to please fans of The Hangover, and the amount of misanthropy on deck in the screenplay is surprising and refreshing. But in the end, it's a road picture - and it's a road that we've been down too many times. - Two and a half out of four stars