The Grinch has a wonderfully awful idea.

All the Whos down in Whoville like Christmas a lot. But the Grinch, who lives just north of Whoville, has unresolved issues from his childhood that manifest themselves in feelings of hostility towards the whole Christmas season.

We all know the original story of the anti-social green guy who lives atop Mount Crumpit and steals the trappings of Christmas from his happy-go-lucky neighbors, only to be redeemed by the resilient holiday spirit of the Whos. Ron Howard's new live-action version of the classic Dr. Seuss book and cartoon takes it a step further, telling us not only how the Grinch carries out his Yuletide crime spree, but why.

Expanding the story means fleshing out the characters. Screenwriters Jeffrey Price and Peter S. Seaman do this by softening the hard-hearted Grinch and giving the sweet natured Whos a mercenary edge. An extended flashback to the Grinch's childhood depicts him as a furry outcast, finally driven to his mountain cave by the scornful taunting of classmates. Mr. Grinch is still a mean one, but his meanness turns to mischief only when provoked.

Cindy Lou visits the Grinch at home.

The Whos, on the other hand, are less pure of spirit than their animated predecessors. (Not too pure of body, either, as we see in a couple quick gags that will hopefully go over the heads of the younger members of the audience.) Except for little Cindy Lou Who (Taylor Momson), a precocious child who is troubled by the glitzy commercialism of the Whoville holiday preparations. She has a run-in with the Grinch and sets out to find out all she can about him, thus setting in motion events that will ultimately spin out of control into a ghastly night of terror, mayhem and Roast Beast pilfering.

Updating beloved classics is a thankless task, and it could certainly be argued that nobody needs a new, splashy version of the Grinch. As a dedicated fan of the original, I was skeptical at the prospect of Hollywood mucking up my favorite holiday special. But the filmmakers manage to weave an entertaining 90-minute movie around the familiar plotline.

What works best in this movie is the humor. I liked the jokiness of the writing, the way the script showed respect for its source material while giving it a few playful tweaks. After barking out a few lines of Seuss' sing-song dialogue, the Grinch stops, horrified, and bellows, "I'm talking in rhyme!" And there's a great action-movie gag during one of the Grinch's run-ins with the Whos that . . . well, I won't ruin it for you.

Jim Carrey's spirited portrayal of the Grinch is the movie's most valuable asset. Not many stars would accept a role that calls for them to be completely unrecognizable to the audience, but Carrey utterly becomes the Grinch. The manic energy and pure, physical comedy are there, beneath the mangy green fur, the pot belly, the creepy, long, tapered fingers, the rounded cheeks and yellow eyes. The verbal wit and comic timing are there, even when delivered in the Grinch's hoarse growl. Carrey makes you believe that his heart is full of unwashed socks, his soul is full of gunk, but he's still, in the words of Cindy Lou, kind of sweet.

The lost pod-racing scene from The Phantom Menace.

Unfortunately, there are also a few things about the movie that don't work so well. One of the most painful was the sappy song that Cindy Lou sings about halfway through, stopping the action cold for a few minutes. Another, I'm sorry to say, is the dog. The animated Max was a cheerful, enthusiastic co-dependent, mistreated by the Grinch, but still a happy, loving and — let's face it — dumb dog. Admittedly, that's easier to pull off in animation, but the live-action Max doesn't really have much of a personality. He's cute as can be, but . . . well, it's time to stop picking on the dog. I feel terrible.

And, while Ron Howard's direction keeps the movie fun and lively, he and production designer Michael Corenblith haven't really created a world on par with the cartoon's. The biggest disappointment for me was the film's lack of visual style. I expected to be swept away to a fantastical land and wowed by the Whos homes, their costumes, their wonderful Christmas toys. I wasn't. With a few notable exceptions (the Lou-Who family's holiday outfits, for example) Whoville was kind of dark and dreary. Is this the best the big budgets of Hollywood could come up with? Watching the movie I couldn't help but wonder what someone like Tim Burton might have created had he been put in charge of Whoville.

Gorilla Pants rating: 3 out of 4 bananas

Best time for a bathroom break: Hit the aisle as soon as the kid starts singing.