“Little Miss Sunshine” is a comedy, despite its dark beginning. Many black comedies never rise above their sorrowful dregs, offering morally uncertain humor, but “Little Miss Sunshine” does something special by being at once dark and degraded, yet glad and joyful.

It is the outrageous story of a family road trip to a beauty pageant, featuring Greg Kinnear as an uninspired motivational speaker, the head of a family bizarre even by today’s glut of dysfunctional family movies.

Other notable performances are logged by Alan Arkin, playing a ribald, heroin-addicted grandfather, and Steve Carell, who brings his proper acting chops as a suicidal Proust scholar sharing a room with his Nietzsche-obsessed nephew. Carell is having a terrific year, with his success in “The 40-Year-Old Virgin” and the hit TV show “The Office,” and it’s likely to continue, thanks to this uplifting comedy.

The center of the movie’s little solar system is the giddy sunshine of Olive, played by Abigail Breslin. She is the unlikely beauty pageant runner-up on her way to California to compete, and her performance will open many mouths in shock and hysterical laughter. She is the gravity that holds the wayward family together.

Enthusiastic festival-goers began spreading the buzz after the film’s premiere, where more than 200 people waited in line for nearly four hours for a chance to buy an extra ticket. Few got into the theater. The showing was at 8:30 a.m., and many of the same people were waiting in a line that began in the early hours of the morning. Both the premiere and 8:30 a.m. showing received enthusiastic and prolonged standing ovations, a rarity at Sundance screenings.

During a question-and-answer session, Carell was the focus of many questions and audience adoration. He even ventured into the crowd to hug a particularly moved fan. When asked about his research for the role, Carell replied, “I guess I’m just an exceptional actor.”