As a modern-day Candide with a mullet, David Spade trades his trademark smarm for grubby charm in this picaresque tour through white-trash America, as imagined by real cool cats whose desks are no doubt accessorized with nodding-head chihuahuas and lava lamps. The good news is that this sentimental comedy is generally sweet natured Joe Dirt may sport an "I Choked Linda Lovelace" T-shirt, but he doesn't mean anything by it. He's a rough-hewn gentleman through and through, so guileless that the whole world realizes a certain fine girl called Brandy (Brittany Daniel) is hot for Joe before he does. The bad news (or perhaps this is the good news, if you're a 10-year-old boy) is that the big yucks (in both senses of that word) are derived from fart lighting, elaborate poo gags, and an attenuated bit about a dog who gets his bits frozen to a porch. When we first meet the tonsorially challenged Joe Dirt (Spade, who also co-wrote the screenplay), he's tooling through the streets of Los Angeles in a muscle car gone to pot, en route to a janitorial job whose big perk is that Joe is allowed to sleep in the boiler room. As he's mopping floors, Joe catches the eye of snotty radio producer Fred (co-writer Fred Wolf) whose boss, acid-tongued on-air personality Zander Kelly (Dennis Miller), is busy spewing "isn't it ironic" witticisms in a studio just down the hall. Joe strikes Fred as a perfect foil for Zander's scorching scorn, but a funny thing happens once the two of them are together on the air. Ignoring the professional scorn slinger's jibes, Joe tells his life's story, a tall tale that begins with his abandonment in a Grand Canyon parking lot at age eight. While searching for his missing family, the perpetually optimistic Joe works at a carnival and an alligator farm, takes a trip in a tooth-shaped hot-air balloon and has a scary encounter with a SILENCE OF THE LAMBS-inspired serial psycho named Buffalo Bob (Brian Thompson). And Zander's jaded audience is captivated even the hard-hearted hipster gets a little teary when fate deals Joe an especially painful knee to the nads. First-time feature director Dennie Gordon keeps things moving at a brisk clip (her background is in episodic TV, including Ally McBeal and The Practice), and the supporting cast includes Christopher Walken, Kid Rock, Fred Ward and an animatronic alligator, all deftly cast and used. --Maitland McDonagh