Curmudgeons, look the other way: Happiness is gaining momentum on the big screen.

A few years ago, we saw how joy could reframe life in 'Happy-Go-Lucky,' and now there's a new documentary striving to understand happiness. The latest feature from Oscar-nominated director Roko Belic ('Genghis Blues'), 'Happy' uses interviews with scientists and everyday people to showcase "a journey from the swamps of Louisiana to the slums of Kolkata in search of what really makes people happy."

When one subject in the trailer leads with "When I was run over by a truck," it sounds a lot like that conversation about happiness from 'Before Sunset.' Remember it? "I read this study where they followed people who won the lottery, and people who had become paraplegic. ... After about six months, as soon as people got used to their new situation, they were more of less the same. ... If they were basically an optimistic, jovial person, they're now an optimistic, jovial person in a wheelchair. If they were a petty, miserable a**hole, they're a petty, miserable a**hole with a new Cadillac, a house and a boat."

The documentary is getting a sneak-preview in L.A. on Feb. 24, and you can check out a trailer after the jump.