There's nothing more satisfying as a movie critic than going into a screening with low expectations and coming out tickled pink and grinning ear to ear, which is exactly what happened to me when I saw "Looney Tunes: Back in Action."

Fully anticipating another gimmick-driven shoulder-shrug of a live-action/cartoon hybrid like 1996's "Space Jam," I hadn't put enough faith in director Joe Dante ("Gremlins," "Small Soldiers"), who has been a rabid aficionado of Warner Bros. cartoons his whole life, and who poured every ounce of that enthusiasm into this screwball flick.

Although it gets off to a weak start with a studio board meeting where the humans are worse actors than the cartoons (and interact with them unconvincingly), after it sluffs off its clumsy plot establishing -- in which Daffy Duck is fired by the suits -- it becomes as truly looney-tooney as a fan of classic Warner shorts could ever dream of.

Paying clever homage to its source material in almost every scene, and bursting at the seams with hilarious B-movie sci-fi and pop culture references, it's a smorgasbord of silliness peppered with surprisingly sharp digs at the shallow, money-driven culture of the studio system.

"You can't fire me! My films have made $950 million," insists Kate Houghton (Jenna Elfman) the ironically humorless WB Vice President of Comedy who is picked as scapegoat when the suits realize that "Wabbit season! Duck season!" cartoons don't work without the duck they stupidly canned.

"That's not a billion," comes the flat reply from a sour-pussed CEO.

So, desperate to keep her job, Kate recruits Bugs Bunny to help her find Daffy and woo (or should I say "Woo, woo-hoo!"?) him back. But the duck's already in a crazy pickle:

(Deep breath now!)

He's helping a failed stuntman/studio security guard (Brendan Fraser) save his father...who is a superspy daylighting as an movie star who plays a superspy (Timothy Dalton)...from the evil clutches of the ACME Corporation...whose insane president (a loopy Steve Martin channeling Robin Williams doing Jerry Lewis) has a diabolical plan to turn mankind into monkeys to build his products...then turn them back into humans that will consume them!

Once Bugs, Daffy, Elfman and Fraser (who has already proven his unabashed cartoony aptitude in "George of the Jungle") find each other, their adventure takes the foursome through the Nevada desert (where ACME "operative" Wile E. Coyote attempts to kill them with typically faulty gadgets) to Las Vegas (a casino called Yosemite Sam's Wooden Nickel to be more precise) and "Area 52" (where monsters from bad 1950s movies like "This Island Earth" are kept in giant mason jars with holes poked in the lids). Then Bugs pulls up the corner of the frame to transport them to Paris (enter Pepe LePew) and the Louvre (where the 'toons are chased through Dali, Munch, Seurat and Lautrec paintings), before heading for the African jungle, the ACME headquarters, and finally, outer space. (Duck Dodgers, anyone?)

It's all quite ridiculous, of course -- and some scenes (like a pointless "Psycho" spoof) and several jokes fall flat -- but it's a delight to become immersed in director Dante's world of inspired comedy chaos that rejuvenates the spirit of the 1940s and '50s Warner Bros. cartoons with such faithful authenticity and deftly daft timing.

Although there is much to relish in this movie for any fan of the "Looney Tunes" (and really, who isn't a fan of the "Looney Tunes"?), the more familiar you are with cartoon minutiae (Fraser's bucket-of-bolts AMC Gremlin sputters with genuine Mel Blanc jalopy noises) and cheesy science fiction, the funnier it gets.

Most people will laugh when a sloppily-animated Scooby Doo and Shaggy turn up in the background of a restaurant scene, chewing out actor Matthew Lillard for his performance as Shaggy in last year's "Scooby" movie. Not everyone will recognize cameos from schlockmeister Roger Corman (seen directing the next "Batman" movie on the WB lot), actor Kevin McCarthy (reprising his role from the original "Invasion of the Body Snatchers") and the villainous robot Daleks from the old BBC time-travel series "Doctor Who."

But I must say, I got a big kick out of being at a kids' movie during which I laughed more and laughed harder than any of the kids in the packed-house preview screening.