Ever since the runaway success of"The Hangover," audiences have eagerly awaited a sequel to the breakout Todd Phillips comedy. While they'll have to wait until next year for "The Hangover 2," the director's new "Due Date" might tide over many of that movie's fans.

A trailer for the film, which stars Robert Downey Jr. and Zach Galifianakis and is out in November, hit the Web on Wednesday, and its tone is reminiscent of the wacky Vegas comedy. Downey  plays Peter Highman, a buttoned-down type who, just before the birth of his first child, is forced into a frantic cross-country road trip with slacker Ethan Tremblay (Galifianakis) after Tremblay gets them both kicked off an airplane.

Judging by the trailer, the road trip produces all kinds of high jinks, as Ethan continually annoys Peter with his eccentricities. We're especially fond of the preview's opening, which starts as a serious moment between the two men, with Peter telling Ethan about how his dad left him as a young boy. That's until Ethan finds humor in the anecdote, breaking out into hysterical laughter and offering up this zinger: "Oh my gosh, my dad would never do that. He loved me!"

Ethan is the type of character Galifianakis excels at playing -- the clueless immature type who takes himself really seriously. Meanwhile, it's nice to see Downey back in a more straitlaced role after his action-hero parts in "Iron Man 2" and "Sherlock Holmes." With Phillips leading them, the movie looks like it will have the kind of manic hysteria that made "The Hangover" so hilarious. And if our expectations weren't lofty enough, during an "Iron Man 2" press junket earlier this year, Downey raised the bar by referring to "Due Date" with this high praise: "It's like the second greatest movie I've ever done.