Due Date

WARNER BROS., MELINDA SUE GORDON
Zach Galifianakis, left, and Robert Downey Jr. are shown in a scene from "Due Date."

At one point in "The Hangover" (2009), Bradley Cooper's character, Phil, says to Alan, played by Zach Galifianakis, "You are literally too stupid to insult."

But here's the thing: Alan isn't stupid. That's what "The Hangover" got right. Alan, we later learn, is kind of a genius. He's naive and childlike and very, very weird. He's driven by an endearing sincerity, and—here's the key—the movie never mocks him, never flat-out laughs at him and doesn't encourage the audience to do so either.

That brings me to "Due Date," which also features Galifianakis as a weird, immature man-boy and reteams the actor with his "Hangover" director, Todd Phillips. This time, Galifianakis' character, an aspiring thespian named Ethan Tremblay, is a buffoon. In "The Hangover," the gangster Mr. Chow (Ken Jeong) laughs at Alan, saying, "It's funny because he's fat." Over and over again, "Due Date" all but says, "It's funny because he's stupid." Ethan feels like a refugee from "Dinner for Schmucks," the horrid summer comedy in which Galifianakis also appeared.

Phillips, whose resume also includes "Old School," is no stranger to raunchy, R-rated comedy. But "Due Date" leans on it to the detriment of its story and characters.

So with the odds stacked against them, Galifianakis and Robert Downey Jr. somehow fight through the screenplay, credited to Phillips and three others, to humanize their characters and earn a few real laughs along the way.

Downey is Peter Highman, an architect in Atlanta on business while his wife (Michelle Monaghan) is set to give birth to their first child at the end of the week. It's hate at first sight when he meets Ethan at the airport and something even stronger than that when an incident on the plane lands them both on the no-fly list and Peter's luggage and wallet on its way home to Los Angeles without him.

Against his better judgment, but with no other option, Peter hitches a ride west in a rental car with Ethan, who is in Atlanta for his father's funeral (and now carries his old man's ashes in a coffee can). Inspired by "Two and a Half Men," Ethan is heading to Hollywood to pursue a career in television.

Peter is an uptight jerk, but given his race against the clock to make it home in time for his wife's scheduled C-section, we can cut him some slack. Ethan is another story. He's obnoxious, probing Peter with an unending stream of inappropriate questions and engaging in behavior that ranges from unseemly to disgusting. Then, just as we're as eager to slug him as Peter is, he'll say something about his father or remind Peter of the huge favor he is doing for him.

Surprisingly, these dramatic moments work better than most of the comedy. Downey has long been a wonderful performer—his personal struggles were the only thing holding him back from becoming the star he is now much earlier in his career—so Galifianakis' acting chops are the revelation. With "The Hangover 2" in production now, I'm afraid he is at risk for typecasting. Hopefully, he follows that with a meaty dramatic role.

For Galifianakis' comedy in its purest form, check out his standup act on his DVD "Live at the Purple Onion."

Greg's Grade: C

(Rated R for language, drug use and sexual content. 95 minutes.)