It would be too easy to disdain the earnest sentimentality on display in Cameron Crowe’s We Bought a Zoo, about a recent widower who, struggling to restore a glimmer of hope to his children’s eyes, retires from city life to raise them in a downtrodden animal park.

It’s based on a true story, of course, though it’s hard to imagine such a Hollywood-ready fairy tale unfolding so neatly off the screen. Cynics will surely scoff at the underlying message – that happiness is worth pursuing at any cost, because it’s better to soak in the sunshine than wallow in a morass of self-pity. Optimism, they’d say, is a sucker’s bet.

Yet Crowe has rarely shied from it, and considering his gambles – including Say Anything… and Almost Famous – you’d have to say he’s won more often than not. Zoo is another improbable triumph. It never tries to hide its joy behind a veil of cynicism, embracing the stranger-than-fiction story of Dartmoor Zoological Park owner Benjamin Mee (Matt Damon) with an enthusiastic bear hug.

It's playing tonight at 7 p.m., as a nationwide sneak preview preceding its Dec. 23 release, at theaters throughout the Bay Area. They include: the AMC Loews Metreon; the AMC Van Ness; the AMC Bay Street in Emeryville; the Century 20 in Daly City; the Century at Tanforan in San Bruno; the Century Hilltop in Richmond; the Century Bayfair in San Leandro; and the Century Northgate in San Rafael. For tickets and more listings, click here.