This is a hellacious highway nightmare, featuring equal parts horror and comedy. The film pits two extremely different personalities against each other on a long road trip, and the results are marginally funny—and frequently monstrous. Peter Highman (Robert Downey Jr.) has a baby on the way, and he needs to get home to his wife (Michelle Monaghan) in Los Angeles, pronto. A series of mishaps, courtesy of the offensive Ethan Tremblay (Zach Galifianakis), gets Peter placed on the no-fly list, stranded in Atlanta with no luggage, no wallet and virtually no hope. Along comes Ethan in a Subaru Impreza, with his French bulldog and his father’s ashes in tow. Directed by Todd Phillips, who also did The Hangover, this isn’t a constant laugh riot. But the leads are good, and there’s enough laughter to put it over the top.